Geotechnical and infrastructural damage due to the 2016 Kumamoto earthquake sequence

An active sequence of earthquakes (foreshock, main-shock, and aftershocks) hit the Kumamoto area (Japan) in April 2016, resulting in 69 deaths and considerable economic loss. The earthquakes induced numerous ground failures and cascading geo-hazards, causing major damage to important infrastructures. The main damage patterns include: (a) surface rupture with widespread subsidence of the surface ground, resulting in damage and disruption to transport infrastructure; (b) landslide and slope failure of mountains causing severe damage, collapse and near-collapse of bridges; and (c) liquefaction in some areas of Kumamoto City. Following the earthquakes, field surveys were conducted to study the damages and to understand the main cause of the observed failures. This technical note provides a summary of the geotechnical and infrastructural damage in Kumamoto and the lessons learnt and future research needs are also highlighted.