Correlation of giant earthquakes with the lunar phase in seven Indo-Pacific subduction zones and around Mongolia

Variation in the approximately semidiurnal tidal force affects earthquake occurrence. This paper statistically demonstrates that giant earthquakes occur at lunar phases specific to particular seismic zones. Careful observation during the lunar cycle, especially when seismicity is occurring, should significantly reduce the damage from giant earthquakes. A case study in which a giant earthquake occurred after seismicity was concentrated within the specific lunar phase is discussed.

Correlation of giant earthquakes with the lunar phase in seven Indo-Pacific subduction zones and around Mongolia

Variation in the approximately semidiurnal tidal force affects earthquake occurrence. This paper statistically demonstrates that giant earthquakes occur at lunar phases specific to particular seismic zones. Careful observation during the lunar cycle, especially when seismicity is occurring, should significantly reduce the damage from giant earthquakes. A case study in which a giant earthquake occurred after seismicity was concentrated within the specific lunar phase is discussed.

Differences Between Scientific Prediction and Subjective Expectation of Focal Region and Seismic Intensity of Nankai Trough Giant Earthquake

This study quantitatively analyzes the differences between the actual focal region of the Nankai Trough Giant Earthquake, which is expected to occur in the future, and the conceptual focal region drawn on the map by 595 students. It also examines the differences between the subjective expectation and the scientific prediction of the seismic intensity at the residence of the respondents, to find out the relationship between such differences and the variables of respondents such as residence, attributes and experiences, and others. As a result of the examination, the following findings are clear: the subjective expectation of the focal region of the Nankai Trough Giant Earthquake deviates largely eastwards; those who have their own residence and parents’ home in the area forecasted to be affected by the Nankai Trough Giant Earthquake recognize the focal region of the earthquake better; and those who have taken measures toward disaster prevention such as stocking goods for emergencies and participating in disaster drills account for a smaller percentage of respondents who underestimated seismic intensity at their residence.

THE RUPTURE PROCESS OF THE 2004 SUMATRA-ANDAMAN EARTHQUAKE VIEWED FROM STRAINMETER DATA

Methods for estimating source time function (STF) and temporal variation of back-azimuth of the earthquake source using volmetric and multi-components strainmeter installed in Japan were developed. By applying those methods to the 2004 Sumatra-Andaman giant earthquake, the STF was estimated using volmetric strain records. The duration was about 700 s and the total moment was 5.2 × 1022 Nm, which were almost consistent with other results using seismometer records. Back-azimuth was successfully estimated by multi-components strain records, but the rupture propagation effect was not observed. Those methods were good tools for rapid estimation of giant earthquake source process and were useful for tsunami warnings.