AIST Stories No1

The Innovative World of AIST28at a glanceTerminologyUsing highly precise and reliable data, there is an expectation that we may be able to ascertain the probability of an impending mega-earthquakes in the Nankai Trough through the accumulation and sharing of observations of “slow slip” phenomena. If so, then it will be possible to devise the necessary earthquake countermeasures at the household, corporate, or national government level. Observation network for the Mega-earthquakes in the Nankai TroughPrecursor phenomena for a mega-earthquakeFluctuation of slow slips beneath deep under the ground.Monitoring underground movements: We want to be of use in mega-earthquake prediction and disaster prevention!Tectono-Hydrology Research Team, Active Fault and Earthquake Research CenterEarthquake prediction research: picking up the pace through discovery of precursor data for earthquakesMega-earthquakes are caused by the massive energy of the earth. Learning from the enormous tsunami of the once in a thousand years Great East Japan Earthquake of 2011, national and local governments are proceeding with reviews of presumption of magnitude of earthquake and tsunami heights and disaster prevention measures.The Presumption of maximum magnitude of a mega-earthquake occurring in the Nankai Trough has been raised to 9. Meanwhile, a working group convened by the Cabinet Office in 2012 released preliminary calculations indicating large-scale damage including potentially more than 400,000 fatalities in an area centered on the Pacific coast from Shizuoka Prefecture to Kochi Prefecture as the result of a very severe earthquake that shocked various sectors of society.How should we prepare for an earthquake when we don’t know when it will come? We live in a country where a mega-earthquake could come at any time but it will be difficult to maintain a high degree of disaster prevention awareness over generations. However, if we can predict with relative precision to what extent a coming earthquake is impending, then we may be able to devise the necessary earthquake countermeasures without underestimating risk.Looking back at history, full-scale earthquake prediction research started in Japan in the 1970s. Fearing a Tokai Earthquake on the scale of magnitude 8, the Large-Scale Earthquake Countermeasures Law was enacted in 1978 and earthquake countermeasures were studied. Observation data from governmental and university research organizations was sent to the Meteorological Agency and monitoring was carried out on a 24-hour basis.In actual fact, the findings of data analysis showed that possible precursor data was observed in the region of the hypocenter during the Great East Japan Earthquake and this fact has accelerated research linked to earthquake prediction.Mega-earthquakes in the Nankai TroughThere are fears of a M 8-9 mega-earthquakes along the Nankai Trough occurring in the near future with the hypocentral region being located at the plate boundary along the Nankai Trough. A monitoring program for the Tokai Earthquake, which is one segment of the mega-earthquakes along the Nankai Trough, has been adopted in accordance with the Act on Special Measures Concerning Countermeasures for Large-Scale Earthquakes (enacted in December 1978).n型材料●Mechanism of the mega-earthquake in the Nankai TroughTsunamiSudden upwardmovement resultsin an earthquakeNankai TroughSlipPhilippineSea PlateAISTsupporting livelihoods! Serving our lives and society in this manner!