The 2017 Mw 7.1 Puebla–Morelos intraslab
earthquake (depth: 57 km) severely hit Popocatépetl Volcano, located
∼ 70 km north of the epicenter. The seismic shaking triggered shallow
landslides on the volcanic edifice, mobilizing slope material saturated by
the 3 d antecedent rainfall. We produced a landslide map based on a
semi-automatic classification of a 50 cm resolution optical image acquired
2 months after the earthquake. We identified hundreds of soil slips and
three large debris flows for a total affected area of 3.8 km2.
Landslide distribution appears controlled by the joint effect of slope
material properties and topographic amplification. In most cases, the
sliding surfaces correspond with discontinuities between pumice-fall and
massive ash-fall deposits from late Holocene eruptions. The largest
landslides occurred on the slopes of aligned ENE–WSW-trending ravines, on
opposite sides of the volcano, roughly parallel to the regional maximum
horizontal stress and to volcano-tectonic structural features. This suggests
transient reactivation of local faults and extensional fractures as one of
the mechanisms that weakened the volcanic edifice and promoted the
largest slope failures. The material involved in the larger landslides
transformed into three large debris flows due to liquefaction. These debris
flows mobilized a total volume of about 106 m3 of material
also including large wood, were highly viscous, and propagated up to 7.7 km
from the initiation areas. We reconstructed this mass wasting cascade by
means of field evidence, samples from both landslide scarps and deposits,
and analysis of remotely sensed and rainfall data. Although
subduction-related earthquakes are known to produce a smaller number of
landslides than shallow crustal earthquakes, the processes described here show how an unusual intraslab earthquake can produce an exceptional impact
on an active volcano. This scenario, not related to the magmatic activity of
the volcano, should be considered in multi-hazard risk assessment at
Popocatépetl and other active volcanoes located along volcanic arcs.
Introduction
Earthquakes can induce large slope instabilities in tectonically active
regions, resulting in a relevant source of hazard and damage. Earthquake
magnitude (M) and the resulting intensity of ground vibration control the
extent of the area where landslides may occur. One of the first
comprehensive historical analyses of earthquake-induced landslides was done
by Keefer (1984), who showed that the maximum area likely to
be affected by landslides during a seismic event increases with M following
a power law scaling relationship. In the following years, a growing number
of studies started focusing on the impact of landsliding caused by
large-magnitude earthquakes along relatively shallow crustal faults. In
particular, it was observed that the fault rupture mechanism strongly
influences the distribution of landslides, which are usually more abundant
on the hanging wall in the case of reverse or normal faults
(Sato et al.,
2007) and present a symmetric distribution in the case of strike-slip faulting
(Xu and Xu, 2014). In the case of co-seismic landslides related
to earthquakes in subduction zones, very few data and inventories are
available (LaHusen
et al., 2020; Schulz et al., 2012; Serey et al., 2019; Wartman et al.,
2013). Best examples are the landslides induced by the 2010 Chile megathrust
earthquake (Serey et al., 2019) and by the 2011
Tohoku earthquake in Japan (Wartman et al.,
2013). In both cases, thousands of shallow landslides were identified, but
the main conclusion of these works is that the number of landslides
generated by megathrust earthquakes is smaller than the number of events
triggered by shallow crustal earthquakes by at least 1 or 2 orders of
magnitude. Today, we know that the spatial distribution of
earthquake-induced landslide is also a function of geological parameters
(e.g., contrast in rock coherence, permeability), topography (slope and
shape), land cover and land use, and ground-motion characteristics such as
amplification and shaking frequency
(Fan et al.,
2019; Von Specht et al., 2019). Concerning the impact of earthquake on
sediment-related hazards, a dramatic increase in sediment yield has been
documented after large earthquake-induced landslides
(Pearce and
Watson, 1986; Dadson et al., 2004; Marc et al., 2019). Progressively, source
areas on highlands can become quickly stable as fine material is removed and
new vegetation grows and stabilizes the slope
(Domènech et al., 2019), but debris
flows can still occur due to the remobilization of deposited material along the
channel (Fan et al., 2021).
On active volcanoes, a large variety of factors can promote slope
instability and failure; these are magma intrusions, hydrothermal activity,
gravitational spreading of the basements, climate fluctuations, and regional
tectonics
(Capra
et al., 2013; Mcguire, 1996; Norini et al., 2008; Roberti et al., 2017;
Roverato et al., 2015). In particular, earthquakes are recognized to play
one of the most important roles in the initiation of slope failures on
volcanoes (Kameda et al., 2019; Sassa, 2005;
Siebert, 2002). Volcanic slopes that are close to a critical state can be
particularly susceptible to perturbations produced by regional earthquakes.
Volcanic landslides include a wide spectrum of instability phenomena, from
small slope failures to large sector collapse evolving into catastrophic
debris avalanches. Intermediate processes such as shallow landslides and
debris flows are common in the case of an earthquake, but they are
relatively poorly documented for past events. Debris flows, often called
lahar in volcanic environments, are usually associated with eruptions that
induce ice melt or snowmelt or with intense rainfalls occurring during
intra-eruptive phases (e.g., Capra et al.,
2018; Major et al., 2016; Manville et al., 2009). Few examples of
long-runout debris flows triggered by earthquakes have been described on
active volcanoes (Schuster et al.,
1996; Scott et al., 2001). In Mexico, a Mw 6.5 earthquake that occurred in
1920 induced several landslides in the Pico de Orizaba–Cofre de Perote
volcanic chain that transformed into debris flows with catastrophic effects
for villages along the Huizilapan ravine (Camacho, 1920;
Flores, 1922). More recently, several thousands of shallow landslides were
triggered by the Tecomán earthquake of 21 January 2003 (Mw 7.6) in the
volcanic highlands north and northwest of Colima City
(Keefer et al., 2006).
In this paper, we investigate the exceptional mass wasting episode triggered
by the 19 September 2017 Mw 7.1 Puebla–Morelos intraslab earthquake
along the eastern and western sides of Popocatépetl Volcano. The seismic
shaking mobilized pre-existing ash and pumice-fall deposits, producing
hundreds of co-seismic soil slips. The largest ones had a total volume of
about 106 m3 and transformed into debris flows that traveled
up to 7.7 km on the western side of the volcanic edifice. This phenomenon,
never studied before at Popocatépetl Volcano and probably unique on an
active stratovolcano along a continental volcanic arc, has important
implications for hazard assessment, as the actual hazard map only includes
the impact of lahars related to volcanic activity
(Martin Del Pozzo et al.,
2017). In the following, we provide a general introduction to the
geomorphology of Popocatépetl Volcano and to its recent volcanic
activity. Then, we describe the impact of the Mw 7.1 Puebla–Morelos
earthquake on the volcano slopes in terms of ground vibrations and landslide
activity. Finally, we reconstruct the transformation of the major landslides
into long-runout debris flows, and we discuss the hazard implication for an
active volcano.
BackgroundPopocatépetl Volcano
Popocatépetl Volcano (19∘03′ N, 98∘35′ W; elevation
5450 m a.s.l.) is located in the central sector of the Trans-Mexican
Volcanic Belt (TMVB) and represents the active and southernmost
stratovolcano belonging to the Sierra Nevada volcanic chain
(Pasquaré et al., 1987) (Fig. 1a, b). The Popocatépetl is a composite volcano, and its present shape
is the result of eruptive activity that rebuilt the modern cone after the
23.5 ka flank collapse (Siebe
et al., 2017). During the Last Glacial Maximum (20–14 ka) glacier activity
resulted in extensive moraines and glacial cirques
(Vázquez-Selem and Heine, 2011). The lower part
of the cone features a gentle slope (10–15∘) and a dense
vegetation cover up to approximately 3800 m a.s.l.
(Fig. 2a), where pine trees became scattered and
surrounded by dense tropical alpine grasslands (zacatonal alpino,
Almeida et al., 1994) that can measure up to 1 m in
height. Then, the cone becomes progressively steeper (20–30∘) and
unvegetated up to the summit. In the upper portion of the cone, the slopes
are covered by abundant unconsolidated ash named “Los Arenales” from the
recent vulcanian eruptions (Fig. 2a).
Quaternary volcanic activity of Popocatépetl Volcano has been
characterized by catastrophic episodes including sector collapses and
Plinian eruptions that emplaced pyroclastic density currents and thick
pumice-fall deposits, predominantly toward the east and northeast
(Fig. 1b)
(Siebe and Macías, 2006). Based
on its Holocene eruptive record, Plinian eruptions at Popocatépetl have
occurred with a variable recurrence time of about 1–3 kyr (Siebe et al., 1996). Since 1994,
the volcano entered a new eruptive phase, which includes dome growths
that are subsequently destroyed during strong vulcanian eruptions with
columns up to 8 km in height, accompanied with ash fall that has been
affecting populations in a radius of approximately 100 km. Eruptive activity
played the primary role in accelerating the glacier retreat on the northern
slope of the volcano
(Julio-Miranda et al., 2008).
In recent time, only two large lahar events were observed along the Huiloac
Gorge (Hg, Fig. 1b), i.e., in 1997 and 2001, associated
with eruptive phases (Capra et al.,
2004). At those times, the Ventorillo glacier was still present on the
northern face of the volcano. Both lahars propagated to the town of Santiago
Xalitzintla (SX, Fig. 1b), located ∼ 15 km E
of the volcano summit. The 1997 lahar originated after a prolonged
explosive activity with emission of ash, which caused the partial melt of
the glacier. The rapid release of water gradually eroded the riverbed and
triggered a debris flow. The 2001 lahar originated from the remobilization
of a pumice flow deposit emplaced over the Ventorillo glacier on the
northern side of the volcano. The event occurred ∼ 5 h after
the pyroclastic flow emplacement, and the debris flow was characterized by a
stable sediment concentration of 0.75
(Capra et al., 2004). In the distal
part, the 1997 lahar transformed into a hyperconcentrated flow, while the
2001 one maintained the characteristics of a debris flow due to its apparent
cohesion conferred by a silty-rich matrix inherited from the pumice flow
deposit. Apart from the Huiloac Gorge, which was characterized by
significant geomorphic transformations due to these latter processes
(Tanarro et al., 2010),
most of the drainage network of Popocatépetl Volcano has a dense
vegetation cover and presents stable, low-energy sediment transport
conditions (Castillo et al.,
2015). These stable conditions suddenly changed during the Mw 7.1
Puebla–Morelos earthquake.
The Mw 7.1 intraslab Puebla–Morelos earthquake
On 19 September 2017, central Mexico was hit by a Mw 7.1 intraslab
seismic event (depth: 57 km) named the Puebla–Morelos earthquake
(Melgar et al., 2018; Singh et
al., 2018). The epicenter of the earthquake was located ∼ 70 km south of the summit of Popocatépetl Volcano and ∼ 100 km south of Mexico
City (Fig. 1b). The focal mechanism corresponds to
a normal fault with a dip angle of 44–47∘
(Melgar et al., 2018). The 2017 Mw 7.1
Puebla–Morelos earthquake produced the most intense ground shaking ever
recorded in Mexico City during a subduction-related earthquake and was the
most damaging event for this densely urbanized part of the country since the
1985 Mw 8.1 Michoacán interplate earthquake, which occurred exactly
32 years before (Singh et al., 2018). The damage
was surprisingly large in the critical frequency range for Mexico City
(0.4–1 Hz), where the earthquake severely damaged hundreds of buildings and
killed 369 people (Singh et al., 2018). The 2017
intraslab earthquake occurred closer to Mexico City, at greater depth, and
involved a higher stress drop than its interplate counterparts, such as the
1985 Michoacán event. The stress drops of intraslab events have been
estimated as being ∼ 4 times greater than that of the interplate earthquakes
(García et al., 2005) and the ground acceleration of the
intraslab earthquakes are expected to be more enriched at higher frequencies
than those of the interplate events (Furumura
and Singh, 2002; Singh et al., 2018). During the 2017 Mw 7.1
Puebla–Morelos earthquake, the peak ground acceleration (PGA) recorded at
station Ciudad Universitaria (CU) was the highest recorded in the last 54
years of observations (57.1 cm s-2) (Singh et
al., 2018). Station CU is located on the external boundary of the
sedimentary basin responsible for the well-known seismic amplification at
Mexico City (Fig. 1b). The strong ground motion
recorded at PPIG station (Fig. 1c), located at
3980 m a.s.l. on Popocatépetl Volcano's slopes, featured a much higher value
of PGA (106.83 cm s-2, 0.1 g) than the one observed at station CU.
Data and methods
We adopted a combined field- and remote-based approach to retrieve
information about the earthquake impact on such a difficult to access
environment. Semi-automated satellite-image classification is a rapidly
developing tool producing reliable landslide maps
(e.g., Fan et al., 2019, and references
therein). We used optical satellite data to identify the main areas affected
by landslides and to constrain the timing of the landslide occurrences with
respect to the earthquake event (Fig. 2a, b). We
constructed a preliminary landslide map (Fig. 2c)
based on the interpretation of an archive Pléiades 1A image (incidence
angle of 14.63∘, resolution of 0.5 m) acquired 2 months after
the earthquake. A normalized difference vegetation index (NDVI) was
calculated using band 1 (red) and band 4 (infrared). The resulting raster
was classified for excluding vegetation cover, roads, and buildings from the
analysis and selecting only landslide scars or depositional areas. The final
map (Fig. 2c) was validated and refined based on
data that we collected in the field. Most landslides are located on the W
side, on the E side, and on the SE side of the volcanic edifice
(Fig. 3).
We conducted four field campaigns from October 2017 to November 2019 to
investigate the morphology and stratigraphy of the source area of main
landslides, to map and measure faults and fractures caused by the
earthquake, and to define the extension, thickness, and textural
characteristics of the larger debris flows (Fig. 4). The stratigraphy on the main landslide scars was reconstructed to
determine texture and physical properties of the tephra layers involved in
the mass wasting process. We selected a soil sample for radiocarbon analysis
to identify the age of the stratigraphic sequence and to define its
distribution. The 14C age was obtained through accelerator mass
spectrometry dating (BETA Analytic Laboratory) and calibrated with the
IntCal20 calibration curve
(Reimer et al., 2020).
We mapped and sampled main debris-flow deposits, and grain size analyses was
performed by dry-sieving for the sand fraction and by means of a laser
particle sizer (Analysette 22) for silt and clay fractions.
We analyzed two Sentinel-1 SAR images (synthetic aperture radar, Copernicus
program) to define the timing between the earthquake and the observed mass
wasting processes (Fig. 9). The analyzed images
were acquired before and after the earthquake (17 and 23 September 2017) in
1A level ground-range-detected, ascending-orbit, interferometric wide-sensor
mode and dual polarization. A radiometric calibration was applied to extract
the most significant amount of backscattering information from the ground
linked to the surficial roughness. As a second step, a change detection
technique named log ratio was applied to detect pixel values directly
related to radar backscattered and correlated to superficial processes; this is
an algorithm used to detect changes using a mean ratio operator between two
images of the same area but taken at different times
(Mondini, 2017; Singh, 1989). Finally, we
analyzed rainfall data gathered at the Altzomoni rain gauge station (ALTZ,
Fig. 1b), located approximately 10 km north of the volcano summit.
ResultsLandslide mapping
The earthquake triggered hundreds of shallow landslides on the volcano
slopes covering a total area of 3.8 km2 (Fig. 2). Soil slips affected the modern soil and part of the unconsolidated
volcaniclastic cover. The five largest slope failures occurred in the basins
of Hueyatlaco and Huitzilac on the west side of the volcanic edifice and in
the basin of Xalipilcayatl on the east (Fig. 4).
The scarps of these landslides were generated at elevations of about
3400–3800 m a.s.l. on the internal faces of ravines or glacial cirques,
where slopes are > 20∘ (Fig. 4c). Sharp rectilinear extensional fractures and small normal faults
parallel to the valley slopes were observed in the Hueyatlaco basin after
the earthquake (Fig. 5a). These faults and
fractures have a maximum length of about 1 km, show displacements of up to
40–50 cm, and are located on the valley flanks (Fig. 5b), suggesting a correlation with local gravitational instability
triggered by seismicity. A cluster of smaller shallow landslides is visible
on the southwestern side of the volcanic cone (Fig. 2c). These landslides were produced by the collapse of the steep slopes of
hummocky hills (Figs. 2, 3b) corresponding to the
debris avalanche deposit of the last major flank failure that occurred at
23.5 ka (Espinasa-Perena
and Martín-Del Pozzo, 2006; Siebe et al., 2017).
(a) Rectilinear extensional fractures and small normal faults opened parallel to the Hueyatlaco ravine (white arrows); background image:
Pléiades 1A image acquired on 13 November 2017. (b) Detail of the normal displacement of about 50 cm (white arrow). Coordinate system WGS84 UTM Zone 14Q.
View of the three main landslides scarps: (a, b) Huitzilac, (c) Hueyatlaco, (d) Xalipilcayatl. In panel (e) the stratigraphic sections of the
scarps and the grain size distributions of their strata (data in Appendix A)
are reported; upper classic Plinian eruptions (UCPES, pink), lower classic
Plinian eruptions (LCPES, orange), and the dated layer are indicated; see
text for more details. (f) Geographic location of sampling points;
background image: Pléiades 1A image acquired on 13 November 2017.
The scarps or the larger landslides located on the western slope of the
volcano show a similar stratigraphy, with the intercalation of pumice- and
ash-fall deposits (Fig. 6a–c). Pumice-fall
deposits consist of open-framework, clast-supported units composed of
gravel–sand-sized fragments of pumice embedded in a matrix of fine material
(from silt to clay). Two main layers of pumice-fall deposit were observed at
the Hueyatlaco and Huitzilac landslide scars (layers B and D, section
PO1906; layers C and E, section PO1927; Fig. 6e).
Another pumice-fall deposit crops out at the base of the pyroclastic
succession. The fallout deposits are intercalated with massive or stratified
ash layers, with variable thicknesses up to 4 m. They mainly consist of sand
(71 %–93 %), silt (16 %–1 %), and less than 1 % of clay (see Appendix A). A
sample from layer C (section PO06) was dated by using 14C, giving a
calibrated age of 537–643 CE (1500 ± 30 BP conventional radiocarbon age)
(Fig. 6e). Based on this age, the two younger
pumice-fall deposits are here correlated with the upper and lower classic
Plinian eruptions (UCPES and LCPES) of the late Holocene, which had a main
dispersal axis towards the east and northeast (Fig. 1b)
(Siebe et al., 1996). The thicker
deposits of these eruptions crop out on the eastern flank of the volcano, as
observed at section PO11, and correspond to the scar of the Xalipilcayatl
landslide (Fig. 6d). Here, a main unit of
pumice-fall deposit (C in Fig. 6d) features a
total thickness of 3.5 m and consists of a massive, clast-supported unit
dominated by coarse fragments barren of any silt and clay fractions. This
latter unit lies on a 10 cm thick sandy layer (B in
Fig. 6d). In all the studied sections, the upper
ash unit corresponds to the products accumulated from the frequent vulcanian
explosions that characterize the modern eruptive activity of the volcano.
Characterization of debris flows and associated deposits
The five largest landslides described in Sect. 4.1 (one each at Hueyatlaco and
Xalipilcayatl and three at Huitzilac) mobilized a total
volume of about 1.35 × 106 m3 of ash- and pumice-fall
deposits (Table 1). Landslide scarps measured 640 m in length and 4 m in depth at Hueyatlaco, 740 m in length and 3 m in depth at Huitzilac, and 400 m in length and 3 m in depth at Xalipilcayatl (Fig. 7). We calculated the volume of the landslides by assuming a constant depth
(with an uncertainty of ±0.5 m) over the area of detachment. We
measured the depth of the main scars in the field while the area of the main
scars was inferred from field surveys and from the inspection of post-event
optical images (Fig. 7).
Main morphometric data of the landslides that occurred in the
headwaters of the Hueyatlaco, Huitzilac, and Xalipilcayatl ravines. The area of
the main scars was inferred from the inspection of post-event optical images
(see Fig. 8). The depth of the scars was measured in the field. The volume
of the landslides was calculated assuming a constant depth (with an
uncertainty of ±0.5 m) over the area of detachment.
Debris-flow deposits in the upper (a–c), intermediate (d–f), and lower reaches (g–h) of the Huitzilac, Hueyatlaco, and Xalipilcayatl basins: (a) scarp of landslide A-1 at Huitzilac (view from point PO06), (b) main channel of the Huitzilac ravine (PO17), (c) main channel of the Hueyatlaco ravine (PO1701), (d) large wood deposits at Hueyatlaco (PO03), (e) overbank deposits at Hueyatlaco (PO02), (f) mud trace on lateral terraces at Huitzilac (HWM: height of watermark) (PO11), (g) evidence of dewatering at Huitzilac (PO19), (h) detail of the lower deposit at Xalipilcayatl (POE04), and (i) grain size distribution of the samples of the deposits.
The landslides transformed into three long-runout debris flows
(Fig. 8). At the Huitzilac ravine, the main landslide
body (landslide A-1, Fig. 7c) impacted the
opposite side of the valley, partly overtopping it
(Figs. 4c and 8a). Two other soil slips (landslide
A-2 and A-3, Fig. 7c) contributed to forming the
subsequent debris flow, which extended up to 7.7 km from the source before
diluting into a streamflow. The total observed thickness of the deposit
measures up to 3 m, but mud traces on standing trees and on lateral terraces
measure up to 10 m on proximal reaches (PO17, Fig. 8b) and up to 1.5 m in distal reaches with horizontal surfaces at benches
(PO11, Fig. 8f). In distal reaches, where the
channel was shallow, the flow inundated large plains (PO15 and PO19). The
deposit is massive and dark-gray in color and mainly consists of sand
(77 %–86 %) with a relevant gravel proportion (15 %) due to pumice
fragment enrichment in proximal reaches (Fig. 8i).
Clay content is less than 1 %. The lower unit consists of coarse-to-medium
ash with evidence of dewatering (Fig. 8g). At
Hueyatlaco, the debris-flow runout extended up to 6.4 km
(Fig. 4). The deposit appears as a main unit,
dark-gray in color, massive, and homogeneous, with a sand fraction consisting of
70 % in proximal reaches (PO01) to 87 % in distal reaches (PO05), with
up to 15 % of silt and less than 1 % of clay
(Fig. 8i; see also Appendix A). Overbank deposits
show sharp edges up to 10 cm thick (PO02, Fig. 8e). The total observed thickness is up to 50 cm
(Fig. 8d; erosion was only incipient at the time
of the observation) but watermarks of up to 5 m were observed in proximal
reaches (PO1701, Fig. 8c). Finally, the deposit in
the Xalipilcayatl ravine extended up to 1.5 km
(Fig. 7f) and is clearly composed of two main
units. The lower unit is massive and dark-gray in color and mostly consists of
sand fraction (88 %, POE03-lower; Fig. 8i), up
to 1.2 m in thickness, while the upper one is massive and pumice-enriched and
represents up to 40 % of the total unit (POE04,
Fig. 8h and i).
We estimate a total entrainment of about 205 000 m3 along both
hillslopes and a channel network assuming 0.5 m of erosion over the area
located downstream from the main scars (Table 2). Large wood (LW) elements
entrained by the initial landslides and the subsequent debris flows
contributed to the final bulk deposits of about 1.632 × 106 m3. The volume of LW was calculated considering a mean tree height of
25 m (measured in the field, with an uncertainty of ±5 m), a mean
trunk diameter of 0.4 m (observed in the field, with an uncertainty of
±0.1 m), and a mean distance of two trees of 10 m (estimated by using
the post-event optical images; see Fig. 7). The
amount of LW recruited in the Huitzilac basin results was 60 000 m3
(±3000 m3), far more than the sum of wood recruitment estimated
for the Hueyatlaco (10 000 ± 500 m3) and Xalipilcayatl (7000 ± 350 m3) basins. The recruited LW stemmed from the combination of
hillslope and channel processes originating from the earthquake-induced
landslides. In general, these landslides were the dominant recruitment
processes in headwaters. In contrast, LW recruitment from lateral bank
erosion became significant in the intermediate reaches of the channels. The
slope area that collapsed into the Xalipilcayatl basin contained most of the
LWs that was later transported by the flow (86 %). In the Huitzilac basin,
the LW recruitment mainly occurred on the slopes located right below the
collapses (62 %), while in the Hueyatlaco basin most came from the channel
banks (75 %). Most of the transported LWs remained trapped by natural
obstacles in the main channel (i.e., standing vegetation) and clogged in the
flat reaches of the channel (Fig. 8d). In the
Xalipilcayatl ravine, most of LW was transported for the whole runout
distance into the main landslide deposit.
Main morphometric data of the debris flows that were observed in
the Hueyatlaco, Huitzilac, and Xalipilcayatl basins. The entrained volume was
calculated assuming 0.5 m of erosion over the area located downstream from
the main scars where the vegetation was destroyed. The volume of large wood
(LW) recruitment was calculated considering a mean tree height of 25 m (with
an uncertainty of ±5 m), a mean trunk diameter of 0.4 m (with an
uncertainty of ±0.1 m), and a mean distance of two trees of 10 m based
on field observations and inspection of post-event optical images.
RunoutDropEntrainmentLW volume(km)height×103×103(m)(m3)(m3)Hueyatlaco6.411605010 ± 0.5Huitzilac7.7120012060 ± 3Xalipilcayatl1.5350357 ± 0.35Timing of the events
Results of Sentinel-1 SAR image processing clearly indicate that both
landslides and debris flows occurred between 17 and 23 September 2017. A
binary image was produced where pixels values are linked to spatial change
that occurred in this time span (Fig. 9a).
Their distribution corresponds with the deposits of the larger debris flows
that occurred in the Huitzilac and Hueyatlaco basins, as is easily observable
in a later optical Sentinel-2 image (Copernicus program) acquired on 18 October 2017 (Fig. 9b).
Rainfall measurements at rain gauge ALTZ from 1 August to 4 October 2017. A total accumulated rainfall of 200 mm was recorded during the
30 d preceding the earthquake, 19.7 mm of which was on 17 September 2017
(red bar). On 4 October 2017, the population of San Juan Tehuixtitlán
noticed the passage of sediment-laden flow in the Hueyatlaco ravine.
A total of 200 mm of accumulated rainfall were recorded during the 30 d
preceding the earthquake, with the accumulation of 19.7 mm 2 d before
the earthquake (Fig. 10). Thus, we expect that the
slope material was wet at the time of the earthquake. Based on the remote-sensing analysis and considering that between 19 and 23 September only a few millimeters of rainfall accumulated (Fig. 10), it is thus
highly probable that both slope failures and debris-flow emplacement were
co-seismic. Witnesses from the town of Atlautla, which is located at the
outlet of the Huitzilac ravine (Fig. 1b), also
confirmed this information. During the following weeks, rainfall remobilized
fine material from the landslide deposits reaching the town of San Juan
Tehuixtitlán (Fig. 4a). On 4 October 2017, the
population of San Juan Tehuixtitlán noticed the transformation of the
shallow water flow of the Hueyatlaco ravine into a hyperconcentrated flow. It
was the first time that this local community located on the western volcano
slope observed such a phenomenon. Rainfall measurement at Altzomoni
rain gauge station (ALTZ, Fig. 1b) shows an
accumulation of 35.7 mm of rainfall over 12 h beginning at 10:00 UTC
on 4 October, with a peak between 20:00 and 21:00 UTC (Fig. 10). The rainfall event of 4 October only remobilized fine material from
the landslide deposits reaching the town of San Juan Tehuixtitlán; the
debris flows along the Huitzilac and Xalipilcayatl were never reported since
they never extended out to any populated area in 2017. During the 2018 and
2019 rainy seasons, the fine sediment remobilized from the debris-flow
deposit in the Huitzilac ravine reached the road connecting San Juan
Tehuixtitlán to Atlautla (Fig. 1b).
DiscussionPredisposing factors to slope instabilities
The Popocatépetl area is tectonically characterized by a Quaternary, roughly
NE–SW- or ENE–WSW-trending maximum horizontal stress regime, responsible for
arc-parallel E–W-striking transtensive faults and NE–SW or ENE–WSW arc-oblique
normal faults (Arámbula-Mendoza
et al., 2010; García-Palomo et al., 2018; Norini et al., 2006, 2019).
This stress regime generated ENE–WSW extensional fracturing and faulting of
the volcanic edifice (Fig. 11), controlling the
orientation and propagation by magmatic overpressure of dikes within the
volcanic cone and recent eruptive fissures on its flanks
(Arámbula-Mendoza
et al., 2010; De Cserna et al., 1988).
The size of the slope failures triggered by the 2017 Mw 7.1
Puebla–Morelos earthquake is highly variable although (i) the epicenter of
the earthquake is far from the volcano, with seismic shaking expected to be
of similar intensity all over the symmetric volcanic cone, and (ii) soil and
recent pyroclastic cover is quite homogeneous on the edifice flanks. Small
shallow landslides occurred all over the volcano flanks, while the few
larger landslides described in our work are limited to the eastern and
western sides of the volcanic cone (Fig. 2). Thus,
seismic shaking originating from the earthquake triggered large (volume
> 105 m3) landslides only in specific sectors of the
volcano flanks.
The location of the larger slope failures defines a sharp ENE–WSW unstable
sector, crossing the volcano summit and parallel to many deep rectilinear
valleys carved in the volcanic cone (Fig. 11). In
this ENE–WSW elongated sector of the volcano, some faults and extensional
fractures were generated by the 2017 earthquake in the same basins
where the larger landslides occurred (Fig. 5).
This configuration suggests strongly localized site effects and/or a
structural control on the location of the slope instability. Indeed, the
unstable sector is roughly parallel to the ENE–WSW maximum horizontal
stress, where local volcano-tectonic structural features are recognized on
the volcano
(Arámbula-Mendoza
et al., 2010; De Cserna et al., 1988). The remobilization of larger
quantities of material in this sector with respect to other areas of the
volcano flanks may be correlated to the presence of ENE–WSW-striking faults
and fractures that progressively weakened the volcanic edifice. Some of
these volcano-tectonic structures may also have undergone transient
reactivation by seismic shaking, increasing local slope deformation by
the opening of fractures that promoted the largest slope failures triggered by
the earthquake.
Initiation of co-seismic landslides
Slopes collapse when the shear stress across a potential failure plane
exceeds the substrate strength. Earthquakes reduce the slope stability and
can cause landslides through the perturbation of the normal and shear
stresses in the slope. In the case of soft, saturated soils, the coalescence of
cracks during earthquakes may results in liquefaction due to the increase in
substrate permeability. At Popocatépetl Volcano, a combination of these two
mechanisms produced the soil slips observed in the headwaters of the Hueyatlaco,
Huitzilac, and Xalipilcayatl basins. Shapiro et al. (2000)
already noticed that a large earthquake occurring in the vicinity of the
volcano may result in flank instability because of the seismic waves
traversing the poorly consolidated material composing the volcanic edifice.
The ground motion during the 2017 earthquake was anomalously large in the
frequency range 0.4–1 Hz, as intraslab earthquakes involve a higher stress
drop than their interplate counterparts (Singh et
al., 2018). Consequently, the ground motion is relatively enriched at high
frequencies as compared with that during interplate earthquakes, which is
dominated by lower-frequency waves (f< 0:5 Hz), and this effect can
contribute to explaining the high value of PGA measured on the volcano
slope.
Unexpectedly large peak accelerations have been recorded along crests of
mountain ridges during several earthquakes (Davis
and West, 1973; Meunier et al., 2008). Topographic amplification of ground
vibrations is primarily due to the reflection or diffraction of seismic waves,
which are progressively focused upwards (Bouchon et al.,
1996; Davis and West, 1973). The constructive interference of reflections
and the associated diffractions of seismic waves increase towards the ridge
crest also due to local geologic factors, giving rise to enhanced ground
accelerations on topographic highs
(Del Gaudio and
Wasowski, 2007; Meunier et al., 2008; Von Specht et al., 2019).
Geli et al. (1988) show that topographic complexity
(presence of neighboring ridges) may be responsible for large crest or base
amplifications resulting in complex amplification–deamplification patterns
and significant differential motions along the slopes. The amplification at
the crest of a mountain can be as large as or larger than the amplification
normally caused by the presence of near-surface unconsolidated layers
(Davis and West, 1973). It is well-known that shallower
earthquakes may cause large landslides
(e.g., Marc et al., 2019), but the
Puebla–Morelos earthquake was moderately deep (i.e., 57 km). The PGA
produced by the 2017 earthquake at station PPIG (106.83 cm s-2) was
about 2 times higher than the PGA observed at CU (57.1 cm s-2).
Indeed, the distance epicenter–PPIG (68 km) is about half the distance
epicenter–CU (111 km), and this partially explains the difference in PGA
observed at the two stations. However, during the earthquake the headwaters
of the Hueyatlaco, Huitzilac, and Xalipilcayatl ravines could have experienced
even higher values of PGA due to the effect of the topographic amplification of
seismic waves. The PGA map produced by the USGS Seismic Hazard Program shows
values between 0.28 g in the southern sector of the cone and up to 0.18 g closer
to the vent (Fig. 2c). The spatial interpolation
of PGA clearly shows the interaction between the energy distribution and the
topography, which played an important role in the location of landslides.
The cluster of smaller landslides located on the southwestern side of the
volcanic cone, closer to the epicenter, is likely due to the combination of
large ground motion and high slopes that consist of debris avalanche
hummocks (Fig. 3b).
The complex topography of Popocatépetl Volcano, characterized by
neighboring ridges and valleys, probably produced local amplification values, which makes it difficult to explain why larger soil slips did not occur in
other similar locations in terms of elevation, slope, and stratigraphy.
However, the deposits located along the ENE–WSW unstable sector of the
volcano (see Sect. 5.1), at an elevation ranging from 3400 to 3800 m and
characterized by a slope > 20∘, appear the most
likely to suffer collapse in the case of an earthquake. This sector of
Popocatépetl Volcano consists of a mantle of loose volcaniclastic material
with the intercalation of silty–sandy ash layers and gravel–sand pumice-fall
deposits (up to 5 m thick; see Fig. 6), covered by
a modern soil with thick alpine grassland. At higher altitude, the steeper
slopes are unvegetated and consist of unconsolidated pyroclastic granular
material where superficial granular flows can be easily observed. The
largest landslides occurred at the boundary of the vegetation line, where pine
trees become scattered but grassland is still abundant
(Fig. 7a, c). The intercalation of layers with
different grain size and the soil coverage probably promotes water
accumulation. Indeed, one mechanism that can possibly explain the collapse
of this material is liquefaction through the disruption of internal,
suspended aquifers. A similar observation was recently made at Nevado del
Huila Volcano, Colombia, during 2007 when lahars originating from large
fractures formed across the summit area of the volcano as a consequence of a
strong hydromagmatic explosion that drained small, perched aquifers
(Johnson et al., 2018). On the
unvegetated portion of the cone, mass remobilization processes such as
raveling and superficial granular flows likely occurred, but without leaving
any scarp, because of the lack of a compacted soil.
Transformation into long-runout debris flows and implications for hazard assessment
Once generated, the earthquake-induced soil slips transformed into debris
flows. The two major debris flows that occurred in the Hueyatlaco and Huitzilac
basins covered a runout distance of 6.4 and 7.7 km, respectively. In
Fig. 12, we show the conceptual model of this
transformation at Popocatépetl Volcano: the propagation of an
earthquake-induced crack in the saturated slope (1) produces a shallow
landslide composed of a mix of ash and pumice. The collapsed material
disaggregates and impacts on the opposite side of the valley (2), and rapidly the
landslide evolves into debris flows, due to the high water content of the
collapsed unconsolidated material (3). The subsequent debris flow is highly
viscous due to the high sand and silt fraction of the mixture
(Fig. 8i) and contains abundant LW entrained along
the channel network, especially along the Huitzilac and Xalipilcayatl
channels, which had entire mature trees incorporated, thus leaving abundant
log-strewn debris. Even if no direct observations are available to assess
whether the collapsed slopes were partially or completely saturated, it is
clear that debris flows contained a large amount of water as observed from
dewatering features of the deposits and high-water marks along the channels
(Fig. 8g). Beginning on 21 August 2017, 138 mm of
rainfall accumulated continuously for 2 weeks, with 19.7 mm just 2 d
before the earthquake (Fig. 10). This large amount
of rainfall was then stored in the open-framework pumice-fall deposits
intercalated by meter-thick sandy layers and in the root fabric of the trees in
the dense forest cover.
Conceptual model of transformation of earthquake-induced soil
slips into debris flows at Popocatépetl Volcano: (1) the earthquake
produces the collapse of the saturated slope composed of a mix of ash and
pumice; (2) the landslide impacts on the opposite side of the valley
entraining a large amount of large wood (LW) and (3) evolves into a debris
flow due to the high water content of the material. The simplified
stratigraphy in (1) reflects the one observed at the scarp of the Huitzilac
landslide (see Fig. 6b).
Volcanoes store or drain water in and through aquifers that can grow and
empty as impermeable barriers develop or as they are breached by
deformation, respectively (Delcamp et al., 2016).
Even if not completely saturated, ground vibrations induced positive pore
pressure and triggered liquefaction and slope failure
(Kameda et al., 2019; Wang
et al., 2019). It is important to note that on 10 August a rainfall of 35 mm, similar to the 4 October event that triggered the sediment-laden flow
observed at San Juan Tehuixtitlán town, did not induce any channel
response, indicating the stability of the slopes of this sector of the
volcano prior to the earthquake. In fact, except for the 2010 lahar that
occurred in the Nexplayantla ravine after 100 mm of accumulated rainfall
(Zaragoza-Campillo et al., 2020), lahars are related to major eruptions,
which explains why the hazard map of Popocatépetl Volcano includes
only rainfall-triggered lahars during or after eruptions
(Martin Del Pozzo et al.,
2017). Detailed field investigations of the role of aquifers on volcanic
landslides are very scarce to date (Delcamp et
al., 2016). Knowledge of the distribution of perched aquifers and the water
content of volcanic deposits can provide precious insights into a complex
mass wasting chain like the one experienced at Popocatépetl Volcano
in 2017.
Finally, it is worth mentioning that during our last field campaign in
November 2019 we observed that the source areas of the larger debris flow
that occurred at the Huitzilac ravine were becoming stable as a result of the
combined effect of the removal of fine material and of the growth of new
vegetation. By contrast, the large amount of material deposited in the
channel remains available for remobilization for many years, resulting in a
remarkable increase in sediment yield as observed in other locations
(e.g., Fan et al., 2021). Indeed, during the 2018
and 2019 rainy seasons, the fine sediment remobilized from the debris-flow
deposits in the Huitzilac ravine reached the road connecting San Juan
Tehuixtitlán to Atlautla.
Conclusions
The catastrophic event of 19 September 2017 at Popocatépetl Volcano is
an exemplary case of interrelated multiple hazards in volcanic environments:
earthquakes, landslides, and sediment-laden flows. During the Mw 7.1
Puebla–Morelos intraslab earthquake, hundreds of shallow landslides were
triggered on the volcano flanks. The combination of strong ground motion due
to local amplification with the presence of water-saturated, tephra-rich
superficial deposits resulted in large slope failures and subsequent
liquefaction of the collapsed material. A total volume of about 106 m3 of volcaniclastic deposits transformed into two large debris
flows on the western slope of the volcano and one on its eastern side. While
the source areas rapidly stabilized in the months and years following, the
fine material deposited in the channels remains exposed to possible
remobilization for many years. These observations imply the need to revise
the hazard assessment for Popocatépetl Volcano, where multi-hazard risk
scenarios should be taken into account, as well as for other volcanic
settings. The mass wasting cascade described here may occur in other
locations, especially in continental volcanic arcs and mountain chains
located in tectonically active regions.
Grain size distributions of samples collected in the landslide scarps and
deposits; cutoff particle sizes: gravel 64–2 mm, sand 2 mm–64 µm, silt 64–2 µm, clay < 2 µm. Refer to Fig. 4 for
sample locations.
The supplement related to this article is available online at: https://doi.org/10.5194/esurf-9-393-2021-supplement.
Author contributions
VC and LC conceived the idea, planned the field activities, and collected most of the data. VC, LC, GN, DF, and EP participated to the field work. VC, LC, and GN wrote the paper. VHMR analyzed seismic data of the PPIG station (SSN-UNAM). ND processed Sentinel-1 and Sentinel-2 images. EP, LC, and VC analyzed the post-event Pléiades image and drew the landslide map. All the authors discussed the results and commented on the paper.
Competing interests
The authors declare that they have no conflict of interest.
Acknowledgements
Seismic data gathered at station PPIG were provided by the Servicio
Sismológico Nacional (SSN – UNAM, México). Rainfall data recorded at
Altzomoni station (Red Universitaria de Observatorios Atmosféricos –
UNAM) were kindly provided by Adolfo Magalli. The authors thank the Department of Innovation, Research University and Museums of the Autonomous Province of Bozen/Bolzano for covering the open-access publication costs. We thank Berlaine Ortega-Flores, Lizeth Cortez, and Lizeth
Caballero-García for their support in the field and in the laboratory.
We are thankful for constructive feedback from Thomas Pierson on an earlier
version of the paper. We thank Matteo Roverato, Ugur Öztürk and two anonymous reviewers, and the associate editor Xuanmei Fan for their detailed comments
and revisions.
Financial support
This research has been supported by the Consejo Nacional de Ciencia y Tecnología (CONACYT-PN 360); Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México (PAPIIT-DGAPA 106419); Ministero degli Affari Esteri e della Cooperazione Internazionale and the AMEXCID (EARFLOW project).
Review statement
This paper was edited by Xuanmei Fan and reviewed by Ugur Öztürk and two anonymous referees.
ReferencesAlmeida, L., Cleef, A. M., Herrera, A., Velazquez, A., and Luna, I.: El
zacatonal alpino del Volcán Popocatépetl, México, y su
posición en las montañas tropicales de América, Phytocoenologia,
22, 391–436, 10.1127/phyto/22/1994/391, 1994.Arámbula-Mendoza, R., Valdés-González, C., and
Martínez-Bringas, A.: Temporal and spatial variation of the stress
state of Popocatépetl Volcano, Mexico, J. Volcanol. Geotherm. Res.,
196, 156–168, 10.1016/j.jvolgeores.2010.07.007, 2010.
Bouchon, M., Schultz, C. A., and Toksoz, M. N.: Effect of three-dimensional
topography on seismic motion, J. Geophys. Res., 101, 5835–5846, 1996.
Camacho, H.: Efectos del temblor sobre el terrano: Chapter V, Tercera Parte,
in: Memoria Relativa al Terremoto Mexicano del 3 de Enero de 1920, Instituto Geológico de México, Ciudad de México, México,
89–94, 1920.Capra, L., Poblete, M. A., and Alvarado, R.: The 1997 and 2001 lahars of
Popocatépetl volcano (Central Mexico): Textural and sedimentological
constraints on their origin and hazards, J. Volcanol. Geotherm. Res.,
131, 351–369, 10.1016/S0377-0273(03)00413-X, 2004.Capra, L., Bernal, J. P., Carrasco-Núñez, G., and Roverato, M.:
Climatic fluctuations as a significant contributing factor for volcanic
collapses. Evidence from Mexico during the Late Pleistocene, Glob. Planet.
Change, 100, 194–203, 10.1016/j.gloplacha.2012.10.017, 2013.Capra, L., Coviello, V., Borselli, L., Márquez-Ramírez, V.-H., and Arámbula-Mendoza, R.: Hydrological control of large hurricane-induced lahars: evidence from rainfall-runoff modeling, seismic and video monitoring, Nat. Hazards Earth Syst. Sci., 18, 781–794, 10.5194/nhess-18-781-2018, 2018.
Castillo, M., Muñoz-Salinas, E., and Arce, J. L.: Evaluación del
sistema erosivo fluvial en el volcán Popocatépetl (México)
mediante análisis morfométricos, Bol. la Soc. Geol. Mex., 67,
167–183, 2015.Dadson, S. J., Hovius, N., Chen, H., Dade, W. B., Lin, J. C., Hsu, M. L.,
Lin, C. W., Horng, M. J., Chen, T. C., Milliman, J., and Stark, C. P.:
Earthquake-triggered increase in sediment delivery from an active mountain
belt, Geology, 32, 733–736, 10.1130/G20639.1, 2004.
Davis, L. L. and West, L. R.: Observed effects of topography on ground
motion, Bull. Seismol. Soc. Am., 63, 283–298, 1973.
De Cserna, Z., De la Fuente-Duch, M., Palacio-Neto, M., Triay, L.,
Mitre-Salazar, L. M., and Mota-Palomino, R.: Estructura geológica,
gravimétrica y relaciones neotectónicas regionales de la Cuenca de
México, Bol. Inst. Geol. UNAM., 104, 71 pp., 1988.Delcamp, A., Roberti, G., and van Wyk de Vries, B.: Water in volcanoes:
evolution, storage and rapid release during landslides, Bull. Volcanol.,
78, 87, 10.1007/s00445-016-1082-8, 2016.Del Gaudio, V. and Wasowski, J.: Directivity of slope dynamic response to
seismic shaking, Geophys. Res. Lett., 34, L12301,
10.1029/2007GL029842, 2007.Domènech, G., Fan, X., Scaringi, G., van Asch, T. W. J., Xu, Q., Huang,
R., and Hales, T. C.: Modelling the role of material depletion, grain
coarsening and revegetation in debris flow occurrences after the 2008
Wenchuan earthquake, Eng. Geol., 250, 34–44,
10.1016/j.enggeo.2019.01.010, 2019.ESA: Copernicus Open Access Hub, available at: https://scihub.copernicus.eu/, last access: 1 April 2020.Espinasa-Perena, R. and Martín-Del Pozzo, A. L.: Morphostratigraphic
evolution of popocatépetl volcano, México, Spec. Pap. Geol. Soc.
Am., 402, 115–137, 10.1130/2006.2402(05), 2006.Fan, X., Scaringi, G., Korup, O., West, A. J., van Westen, C. J., Tanyas,
H., Hovius, N., Hales, T. C., Jibson, R. W., Allstadt, K. E., Zhang, L.,
Evans, S. G., Xu, C., Li, G., Pei, X., Xu, Q., and Huang, R.:
Earthquake-Induced Chains of Geologic Hazards: Patterns, Mechanisms, and
Impacts, Rev. Geophys., 57, 421–503, 10.1029/2018RG000626, 2019.Fan, X., Yunus, A. P., Scaringi, G., Catani, F., Siva Subramanian, S., Xu,
Q., and Huang, R.: Rapidly Evolving Controls of Landslides After a Strong
Earthquake and Implications for Hazard Assessments, Geophys. Res. Lett.,
48, 1–12, 10.1029/2020GL090509, 2021.
Flores, T.: Efectos geologicos: Chapter IV, Primera Parte, in: Memoria del
terremoto Mexicano del 3 de enero de 1920, Instituto Geológico de México, Ciudad de México, México, 27–29, 1922.
Furumura, T. and Singh, S. K.: Regional Wave Propagation from Mexican
Subduction Zone Earthquakes: The Attenuation Functions for Interplate and
Inslab Events, Bull. Seismol. Soc. Am., 92, 2110–2125, 2002.García, D., Singh, S. K., Herra, M., Ordaz, M., and Pacheco, J. F.:
Inslab Earthquakes of Central Mexico: Peak Ground-Motion Parameters and
Response Spectra, Bull. Seismol. Soc. Am., 95, 2272–2282,
10.1785/0120050072, 2005.García-Palomo, A., Macías, J. L., Jiménez, A., Tolson, G.,
Mena, M., Sánchez-Núñez, J. M., Arce, J. L., Layer, P. W.,
Santoyo, M. Á., and Lermo-Samaniego, J.: NW-SE Pliocene-Quaternary
extension in the Apan-Acoculco region, eastern Trans-Mexican Volcanic Belt,
J. Volcanol. Geotherm. Res., 349, 240–255,
10.1016/j.jvolgeores.2017.11.005, 2018.
Geli, L., Bard, P., and Jullien, B.: The Effect Of Topography On Earthquake
Ground Motion: A Review And New Results, Bull. Seismol. Soc. Am., 78,
42–63, 1988.Johnson, P. J., Valentine, G. A., Stauffer, P. H., Lowry, C. S., Sonder, I.,
Pulgarín, B. A., Santacoloma, C. C., and Agudelo, A.: Groundwater
drainage from fissures as a source for lahars, Bull. Volcanol., 80, 39,
10.1007/s00445-018-1214-4, 2018.Julio-Miranda, P., Delgado-Granados, H., Huggel, C., and Kääb, A.:
Impact of the eruptive activity on glacier evolution at Popocatépetl
Volcano (México) during 1994-2004, J. Volcanol. Geotherm. Res.,
170, 86–98, 10.1016/j.jvolgeores.2007.09.011, 2008.Kameda, J., Kamiya, H., Masumoto, H., Morisaki, T., Hiratsuka, T., and Inaoi,
C.: Fluidized landslides triggered by the liquefaction of subsurface
volcanic deposits during the 2018 Iburi–Tobu earthquake, Hokkaido, Sci.
Rep., 9, 1–6, 10.1038/s41598-019-48820-y, 2019.Keefer, D. K.: Landslides caused by earthquakes, GSA Bull., 95, 406–421,
10.1016/0148-9062(85)92394-0, 1984.Keefer, D. K., Wartman, J., Navarro Ochoa, C., Rodriguez-Marek, A., and
Wieczorek, G. F.: Landslides caused by the M 7.6 Tecomán, Mexico
earthquake of January 21, 2003, Eng. Geol., 86, 183–197,
10.1016/j.enggeo.2006.02.017, 2006.LaHusen, S. R., Duvall, A. R., Booth, A. M., Grant, A., Mishkin, B. A.,
Montgomery, D. R., Struble, W., Roering, J. J., and Wartman, J.: Rainfall
triggers more deep-seated landslides than Cascadia earthquakes in the Oregon
Coast Range, USA, Sci. Adv., 6, eaba6790, 10.1126/sciadv.aba6790, 2020.Major, J. J., Bertin, D., Pierson, T. C., Amigo, A., Iroumé, A., Ulloa,
H., and Castro, J.: Extraordinary sediment delivery and rapid geomorphic
response following the 2008–2009 eruption of Chaitén Volcano, Chile,
Water Resour. Res., 52, 5075–5094, 10.1002/2015WR018250, 2016.Manville, V., Németh, K., and Kano, K.: Source to sink: A review of three
decades of progress in the understanding of volcaniclastic processes,
deposits, and hazards, Sediment. Geol., 220, 136–161,
10.1016/j.sedgeo.2009.04.022, 2009.Marc, O., Behling, R., Andermann, C., Turowski, J. M., Illien, L., Roessner, S., and Hovius, N.: Long-term erosion of the Nepal Himalayas by bedrock landsliding: the role of monsoons, earthquakes and giant landslides, Earth Surf. Dynam., 7, 107–128, 10.5194/esurf-7-107-2019, 2019.
Martin Del Pozzo, A. L., Alatorre Ibargüengoitia, M., Arana Salinas, L.,
Bonasia, R., Capra Pedol, L., Cassata, W., Córdoba, G., Cortés
Ramos, J., Delgado Granados, H., Ferrés López, M. D., R., F. Á.,
García Reynoso, J. A., Gisbert, G., Guerrero López, D. A., Jaimes
Viera, M. C., Macías Vázquez, J. L., Nieto Obregón, J., Nieto
Torres, A., Paredes Ruiz, P. A., Portocarrero Martínez, J., Renne, P.,
Rodríguez Espinosa, D. M., Salinas Sánchez, S., Siebe Grabach, C., and Tellez Ugalde, E.: Estudios geológicos y actualización del mapa
de peligros del volcán Popocatépetl, Monografías Instituto de
Geofísica, UNAM, Ciudad de México, México, 2017.Mcguire, W. J.: Volcano instability: A review of contemporary themes, Geol.
Soc. Spec. Publ., 110, 1–23, 10.1144/GSL.SP.1996.110.01.01, 1996.Melgar, D., Pérez-Campos, X., Ramirez-Guzman, L., Spica, Z.,
Espíndola, V. H., Hammond, W. C., and Cabral-Cano, E.: Bend Faulting at
the Edge of a Flat Slab: The 2017 Mw 7.1 Puebla-Morelos, Mexico Earthquake,
Geophys. Res. Lett., 45, 2633–2641, 10.1002/2017GL076895, 2018.Meunier, P., Hovius, N., and Haines, J. A.: Topographic site effects and the
location of earthquake induced landslides, Earth Planet. Sci. Lett.,
275, 221–232, 10.1016/j.epsl.2008.07.020, 2008.Mondini, A. C.: Measures of spatial autocorrelation changes in multitemporal
SAR images for event landslides detection, Remote Sens., 9, 554,
10.3390/rs9060554, 2017.Norini, G., Groppelli, G., Lagmay, A. M. F., and Capra, L.: Recent
left-oblique slip faulting in the central eastern Trans-Mexican Volcanic
Belt: Seismic hazard and geodynamic implications, Tectonics, 25, 1–21,
10.1029/2005TC001877, 2006.Norini, G., Capra, L., Groppelli, G., and Lagmay, A. M. F.: Quaternary sector
collapses of Nevado de Toluca volcano (Mexico) governed by regional
tectonics and volcanic evolution, Geosphere, 4, 854–871,
10.1130/GES00165.1, 2008.Norini, G., Carrasco-Núñez, G., Corbo-Camargo, F., Lermo, J., Rojas,
J. H., Castro, C., Bonini, M., Montanari, D., Corti, G., Moratti, G.,
Piccardi, L., Chavez, G., Zuluaga, M. C., Ramirez, M., and Cedillo, F.: The
structural architecture of the Los Humeros volcanic complex and geothermal
field, J. Volcanol. Geotherm. Res., 381, 312–329,
10.1016/j.jvolgeores.2019.06.010, 2019.
Pasquaré, G., Vezzoli, L., and Zanchi, A.: Morphological and structural
model of Mexican Volcanic Belt, Geofísica Int., 26, 159–175, 1987.
Pearce, A. J. and Watson, A. J.: Effects of earthquake-induced landslides on
sediment budget and transport over 50-yr period, Geology, 14, 52–55, 1986.Reimer, P. J., Austin, W. E. N., Bard, E., Bayliss, A., Blackwell, P. G.,
Bronk Ramsey, C., Butzin, M., Cheng, H., Edwards, R. L., Friedrich, M.,
Grootes, P. M., Guilderson, T. P., Hajdas, I., Heaton, T. J., Hogg, A. G.,
Hughen, K. A., Kromer, B., Manning, S. W., Muscheler, R., Palmer, J. G.,
Pearson, C., Van Der Plicht, J., Reimer, R. W., Richards, D. A., Scott, E.
M., Southon, J. R., Turney, C. S. M., Wacker, L., Adolphi, F., Büntgen,
U., Capano, M., Fahrni, S. M., Fogtmann-Schulz, A., Friedrich, R.,
Köhler, P., Kudsk, S., Miyake, F., Olsen, J., Reinig, F., Sakamoto, M.,
Sookdeo, A., and Talamo, S.: The IntCal20 Northern Hemisphere Radiocarbon Age
Calibration Curve (0–55 cal kBP), Radiocarbon, 62, 725–757,
10.1017/RDC.2020.41, 2020.Roberti, G., Friele, P., van Wyk de Vries, B., Ward, B., Clague, J. J.,
Perotti, L., and Giardino, M.: Rheological evolution of the Mount Meager 2010
debris avalanche, southwestern British Columbia, Geosphere, 13, 1–22,
10.1130/GES01389.1, 2017.Roverato, M., Cronin, S., Procter, J., and Capra, L.: Textural features as
indicators of debris avalanche transport and emplacement, Taranaki volcano,
Bull. Geol. Soc. Am., 127, 3–18, 10.1130/B30946.1, 2015.RUOA-UNAM: Observatorio Atmosférico Altzomoni, available at: https://www.ruoa.unam.mx/index.php?page=estaciones&id=2, last access: 1 April 2021.Sassa, K.: Landslide disasters triggered by the 2004 Mid-Niigata Prefecture
earthquake in Japan, Landslides, 2, 135–142,
10.1007/s10346-005-0054-4, 2005.Sato, H. P., Hasegawa, H., Fujiwara, S., Tobita, M., Koarai, M., Une, H., and
Iwahashi, J.: Interpretation of landslide distribution triggered by the 2005
Northern Pakistan earthquake using SPOT 5 imagery, Landslides, 4,
113–122, 10.1007/s10346-006-0069-5, 2007.Schulz, W. H., Galloway, S. L., and Higgins, J. D.: Evidence for earthquake
triggering of large landslides in coastal Oregon, USA, Geomorphology,
141–142, 88–98, 10.1016/j.geomorph.2011.12.026, 2012.Schuster, R. L., Nieto, A. S., O'Rourke, T. D., Crespo, E., and Plaza-Nieto,
G.: Mass wasting triggered by the 5 March 1987 Ecuador earthquakes, Eng.
Geol., 42, 1–23, 10.1016/0013-7952(95)00024-0, 1996.
Scott, K. M., Macias, J. L., Naranj, J. A., Rodriguez, S., and McGeehin, J.
P.: Catastrophic debris flows transformed from landslides in volcanic
terrains: mobility, hazard assessment and mitigation strategies, USGS
Professional Paper 1630, US Department of the Interior, US Geological Survey, 2001.Serey, A., Piñero-Feliciangeli, L., Sepúlveda, S. A., Poblete, F.,
Petley, D. N., and Murphy, W.: Landslides induced by the 2010 Chile
megathrust earthquake: a comprehensive inventory and correlations with
geological and seismic factors, Landslides, 16, 1153–1165,
10.1007/s10346-019-01150-6, 2019.Shapiro, N. M., Singh, S. K., Iglesias-Mendoza, A., Cruz-Atienza, V. M., and
Pacheco, J. F.: Evidence of low Q below Popocatpetl volcano, and its
implication to seismic hazard in Mexico City, Geophys. Res. Lett., 27,
2753–2756, 10.1029/1999GL011232, 2000.
Siebe, C. and Macías, J. L.: Volcanic hazards in the Mexico City
metropolitan area from eruptions at Popocatépetl, Nevado de Toluca, and
Jocotitlán stratovolcanoes and monogenetic scoria cones in the Sierra
Chichinautzin Volcanic Field, Geological Society of America, Boulder, Colorado, USA, 77 pp., 2006.Siebe, C., Abrams, M., Macías, J. L., and Obenholzner, J.: Repeated
volcanic disasters in Prehispanic time at Popocatépetl, central Mexico:
Past key to the future?, Geology, 24, 399–402,
10.1130/0091-7613(1996)024<0399:RVDIPT>2.3.CO;2,
1996.Siebe, C., Salinas, S., Arana-Salinas, L., Macías, J. L., Gardner, J., and Bonasia, R.: The ∼ 23,500 y 14C BP White Pumice Plinian
eruption and associated debris avalanche and Tochimilco lava flow of
Popocatépetl volcano, México, J. Volcanol. Geotherm. Res., 333–334,
66–95, 10.1016/j.jvolgeores.2017.01.011, 2017.Siebert, L.: Landslides resulting from structural failure of volcanoes, Rev.
Eng. Geol., 15, 209–235, 10.1130/REG15-p209, 2002.Singh, A.: Review article digital change detection techniques using
remotely-sensed data, Int. J. Remote Sens., 10, 689–1003,
10.1007/BF02197115, 1989.Singh, S. K., Reinoso, E., Arroyo, D., Ordaz, M., Cruz-Atienza, V.,
Pérez-Campos, X., Iglesias, A., and Hjörleifsdóttir, V.: Deadly
Intraslab Mexico Earthquake of 19 September 2017 (Mw 7.1): Ground Motion and
Damage Pattern in Mexico City, Seismol. Res. Lett., 89, 2193–2203,
10.1785/0220180159, 2018.Tanarro, L. M., Andrés, N., Zamorano, J. J., Palacios, D., and Renschler,
C. S.: Geomorphological evolution of a fluvial channel after primary lahar
deposition: Huiloac Gorge, Popocatépetl volcano (Mexico), Geomorphology,
122, 178–190, 10.1016/j.geomorph.2010.06.013, 2010.
Vázquez-Selem, L. and Heine, K.: Late Quaternary Glaciation in Mexico,
Developments in Quaternary Science, 15, 849–861, 2011.von Specht, S., Ozturk, U., Veh, G., Cotton, F., and Korup, O.: Effects of finite source rupture on landslide triggering: the 2016 Mw 7.1 Kumamoto earthquake, Solid Earth, 10, 463–486, 10.5194/se-10-463-2019, 2019.Wang, F., Fan, X., Yunus, A. P., Siva Subramanian, S., Alonso-Rodriguez, A.,
Dai, L., Xu, Q., and Huang, R.: Coseismic landslides triggered by the 2018
Hokkaido, Japan (Mw 6.6), earthquake: spatial distribution, controlling
factors, and possible failure mechanism, Landslides, 16, 1551–1566,
10.1007/s10346-019-01187-7, 2019.Wartman, J., Dunham, L., Tiwari, B., and Pradel, D.: Landslides in eastern
Honshu induced by the 2011 Off the Pacific Coast of Tohoku earthquake, Bull.
Seismol. Soc. Am., 103, 1503–1521, 10.1785/0120120128, 2013.Worden, C. B., Wald, D. J., Allen, T. I., Lin, K., Garcia, D., and Cua, G.: A revised ground-motion and intensity interpolation scheme for ShakeMap, B. Seismol. Soc. Am., 100, 3083–3096, 10.1785/0120100101, 2010 (data available at: https://earthquake.usgs.gov/earthquakes/eventpage/us2000ar20/shakemap/pga, last access: 1 February 2021).
Xu, C. and Xu, X.: Statistical analysis of landslides caused by the Mw 6.9
Yushu, China, earthquake of April 14, 2010, Nat. Hazards, 72, 871–893,
10.1007/s11069-014-1038-2, 2014.Zaragoza-Campillo, G., Caballaero, L., Capra, L., and Nieto, A.: Origen, características y peligros asociados a lahares secundarios en el volcán Popocatépetl: el caso del lahar Nexpayantla, Revista Mexicana de Ciencias Geolologicas, 37, 121–134, 10.22201/cgeo.20072902e.2020.2.1565, 2020.