We use broadband seismic recordings to trace the dynamic process of the deep‐seated Akatani landslide that occurred on the Kii Peninsula, Japan, which is one of the best recorded large slope failures. Combining analyses of the seismic records with precise topographic surveys done before and after the event, we can resolve a detailed time history of the mass movement. During 50 s of the large landslide, we observe a smooth initiation, acceleration with changes in basal friction, and reversal of the momentum when the mass collides with the opposite valley wall. Of particular importance is the determination of the dynamic friction during the landslide. The coefficient of friction is estimated to be 0.56 at the beginning of the event and drops to 0.38 for most of the sliding. The change in the frictional level on the sliding surface may be due to liquefaction or breaking of rough patches and contributes to the extended propagation of the large landslide.

Large deep‐seated landslides occurred in Nara, Wakayama, and Mie prefectures of western Japan when Typhoon Talas passed through the region on September 3–4, 2011. Signals of large landslides have been recorded by seismic networks around the world, and overall force estimates have been previously determined for large landslides using long‐period waves. This study focuses on the high‐frequency waveforms and presents signals of 18 landslides caused by Typhoon Talas (2011). The location of the landslides can be determined by a seismological back‐projection technique and these locations correlate with the observed surface features. We have found that the volumes of the landslide correlated with an energy parameter derived from the seismic records.

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These results suggest that the chemical and structural changes of freshly precipitated 14 amorphous ferric hydroxide with short aging time affect their ability, such as iron 15 solubility and dissolution rate, to supply bioavailable iron for the phytoplankton growth. 16The chemical and structural conversion of solid iron phases with time is one of the most 17 important processes in changing the supply of available iron to marine phytoplankton in 18 estuarine and coastal waters and in iron fertilization experiments.

Abstract. The 2016 Kumamoto earthquake sequence was triggered by an M w 6.2 event at 21:26 on 14 April. Approximately 28 h later, at 01:25 on 16 April, an M w 7.0 event (the mainshock) followed. The epicenters of both events were located near the residential area of Mashiki and affected the region nearby. Due to very strong seismic ground motion, the earthquake produced extensive damage to buildings and infrastructure. In this paper, collapsed buildings were detected using a pair of digital surface models (DSMs), taken before and after the 16 April mainshock by airborne light detection and ranging (lidar) flights. Different methods were evaluated to identify collapsed buildings from the DSMs. The change in average elevation within a building footprint was found to be the most important factor. Finally, the distribution of collapsed buildings in the study area was presented, and the result was consistent with that of a building damage survey performed after the earthquake.