The rainfall threshold for debris flow occurrence was evaluated on Mt. Fuji, Japan. Debris flows during frozen periods were triggered by a smaller magnitude of rainfall than during unfrozen periods. During unfrozen periods, the threshold of maximum hourly rainfall intensity triggering debris flow was higher when the volume of channel deposits was larger. The results suggest that the occurrence of frozen ground needs to be monitored for better debris flow disaster mitigation in cold regions.

Reconstructing the growth and decay of past ice sheets is critical to understand relationships between global climate and sea-level change. We take advantage of large wind-farm datasets in the southern North Sea to investigate buried landscapes left by ice sheet advance and retreat occurring about 160 000 years ago. We demonstrate the utility of offshore wind-farm data in refining palaeo-ice sheet margin limits and providing insight into the processes influencing marginal ice sheet dynamics.

We carry out laboratory experiments to investigate the formation and propagation dynamics of exogenous sediment pulses in mountain rivers. We show that the ability of a self-formed deposit to destabilize and generate sediment pulses depends on the sand content of the mixture, while each pulse turns out to be formed by a front, a body, and a tail. Seismic measurements reveal a complex and non-unique dependency between seismic power and sediment pulse transport characteristics.

Natural rock arches are valued landmarks worldwide. As ongoing erosion can lead to rockfall and collapse, it is important to monitor the structural integrity of these landforms. One suitable technique involves measurements of resonance, produced when mainly natural sources, such as wind, vibrate the spans. Here we explore the use of two advanced processing techniques to accurately measure the resonant frequencies, damping ratios, and deflection patterns of several rock arches in Utah, USA.

We performed controlled helicopter flights near seven rock arches and towers in Utah, USA, and recorded how their natural vibrations changed as the helicopter performed different maneuvers. We found that arches and towers vibrate up to 1000 times faster during these flights compared to time periods just before the helicopter's approach. Our study provides data that can be used to predict long-term damage to culturally significant rock features from sustained helicopter flights over time.

This study provides amphibious investigations of debris flow fans (DFFs). We characterize active DFFs, combining laser scan and sonar surveys at Plansee. We discover a 4000-year debris flow record in sediment cores, providing evidence for a 7-fold debris flow frequency increase in the 20th and 21st centuries, coincident with 2-fold enhanced rainstorm activity in the northern European Alps. Our results indicate climate change as being the main factor controlling debris flow activity.

Here we use topographic and ¹⁰Be concentration data to optimise a coastal evolution model. Cliff retreat rates are calculated for two UK sites for the past 8000 years and, for the first time, highlight a strong link between the rate of sea level rise and long-term cliff retreat rates. This method enables us to study past cliff response to sea level rise and so to greatly improve forecasts of future responses to accelerations in sea level rise that will result from climate change.

As rocks are transported, they undergo two attrition mechanisms: chipping, shallow cracking at low collision energies; and fragmentation, significant fracture growth from high-energy impacts. We examine the mass and shape evolution of concrete particles in a rotating drum to experimentally delineate the boundary between chipping and fragmentation. By connecting the mechanics of these attrition processes to resulting shape evolution, we can use particle shape to infer past transport conditions.

We examine stream-power incision and linear diffusion landscape evolution models with and without incision thresholds. We present a steady-state relationship between curvature and the steepness index, which plots as a straight line. We view this line as a counterpart to the slope–area relationship for the case of landscapes with hillslope diffusion. We show that simple shifts and rotations of this line graphically express the topographic response of landscapes to changes in model parameters.