Investigation into the seismogenic process of three earthquakes with about Mw9.0 in the globle in 21 century
In this article,the seismogenic process for three massive earthquakes(Mw≈9.0)that occurred in the world in this century was systematically investigated.The increasing stress stage and the subsequent critical state revealed by the rock mechanics experiment were confirmed in the actual seismogenic process.In this analysis,the tectonic stress was detected by jointly using apparent stress and the b-value.Furthermore,the P-value,a statistical test parameter that depicts the correlation between seismicity and Earth's rotation,can be used to estimate the critical state that the stressed medium in and around the epicenter may approach.The obtained results are shown as follows:Before the three enormous earthquakes,the tectonic stress showed a continuous increasing process,lasting about 6～10 years.We mapped the spatial distribution of the relative changes in b value and found an area with higher relative decreases in b value in and around the rupture zone before the earthquake occurred,reflecting larger values of stress increase in this area.Lower P-values(＜5％)indicate a significant correlation between seismicity and the Earth's rotation namely,the related seismic area could reach a critical state.The analysis of P-value vs.time showed that lower P-values usually occurred within～4 years before the occurrence of the mainshock.Lower P-values(＜2％)correlated well with the epicenter when the P-value reached the lowest.The area with lower P-values is extremely unstable,therefore the rupture initiates around it is reasonable.Similar results obtained from other case studies are also provided in this text.The findings of this study are highly significant for earthquake prediction in real-time as well as for the practical study of the seismogenic process by rock mechanics experiment and the guidance of earthquake prediction by experimental results.
Earthquakes with about Mw9.0Seismogenic processStress increaseCritical stateEarthquake prediction
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