Sequential processes in a landslide hazard at a slate quarry in Okayama, Japan

Abstract

The 12 March 2001 landslide at a slate quarry in Okayama, Japan killed three workers. Composite studies based on field surveys of the landslide slope, interviews with local residents and quarry workers, and inspections of hydrological and seismological data have been used to clarify the causes of this slide and its movements. The results indicate that the landslide was enabled firstly by the steepness of the slope, which had been undercut by river; secondly, the structure was that of a dip-slope that was prone to deepseated slides along bedding planes; thirdly, numerous joints and faults were present. Surprisingly, rainfall, earthquakes, and explosions do not appear to have played any role in the triggering of this slide. The interviews demonstrated that the frequency of precursory failures increased over a period of several hours before the 12 March 2001 landslide. Inspection of the seismograph records and the eyewitness evidence both indicate that the main part of the landslide consisted of two phases of slope failure within 23 s. After the slide, the frequency of the failures gradually decreased with time over a period of several days. Three new terms are proposed for landslides: foreslide, mainslide, and afterslide, following the terms foreshock, main shock, and aftershock used in seismology.

Prediction of a landslide and analysis of slide motion with reference to the 2004 Ohto slide in Nara, Japan

“…The main slide occurred around 0:15 AM on August 10, 2004 followed by subsequent minor slides Gojo Civil Engineering Office, 2004). The subsequent slides may be called afterslides (Suwa et al, 2008). The 2nd slide occurred late in the same morning, the 3rd at 10:30 PM on August 12, and the 4th at 7 PM on August 17.…”

Pulsation in Debris Flows and its Mechanism

“…Recently, time of landslides often detected by seismometer networks and analyzed to discuss their processes [e.g., Suwa et al, 2008;Yamada et al, 2012]. And relationship between the time of landslide and the time of debris-flow hazards is discussed [e.g., .…”

Mechanism and Stability Analysis of Deformation Failure of a Slope

“…e above landslide stability analysis is based on the limit equilibrium state. However, landslide damage is a process of gradual development [33][34][35][36][37][38][39][40]. at is, some zones are in the postfailure stress state, some zones are in the critical stress state, some zones are in the prepeak stress state [41,42], and some zones are in the small deformation state, and this evolution process changes with changes in the environment.…”