Jour. Geol. Soc. Japan, Vol. 120, Supplement, p. 165–184, August 2014 JOI: DN/JST.JSTAGE/geosoc/2014.0012 doi: 10.5575/geosoc.2014.0012 Traces of paleo-earthquakes and tsunamis along the eastern Nankai Trough and Sagami Trough, Pacific coast of central Japan* Osamu Fujiwara1 Overview Received February 17, 2014 Great earthquakes of M8 and above and accompanying tsunamis have Accepted April 15, 2014 repeatedly occurred in the Nankai and Sagami Trough regions. These * Tsunami Hazards and Risks, JGS-GSL Inter- events have caused severe damage to the coastal areas close to the national Symposium, Excursion Guidebook 1 Geological Survey of Japan, National Insti- troughs. As part of the response to the 2011 off the Pacific Coast of tute of Advanced Industrial Science and Tohoku Earthquake (or the Great East Japan Earthquake) and tsunami, Technology (AIST), Tsukuba Central 7, 1-1- 1 Higashi, Tsukuba, 305-8567, Japan. the Cabinet office of the central Japanese Government proposed new guidelines for assessing the risk of similar earthquakes and tsunamis Corresponding author; O. Fujiwara, affecting the Nankai and Sagami Trough regions. These new guidelines
[email protected] call for the largest possible class of earthquake and tsunami to be taken into account even if the probability of such an event is low. Large earthquakes and tsunamis in this region would affect an area with high concentrations of population and industrial infrastructure. As a result of these changes, the last 2 years have seen a high public awareness of disaster mitigation measures in the region. One of the results has been that some local governments have begun upgrading their existing disaster prevention infrastructure, such as raising the height of existing dikes and reinforcing refuges to help protect the population in the case of future great earthquake and tsunami events.