Case 16: Precursory Changes Before the Nankai Earthquake of 1946, in Some Precursors Prior to Recent Great Earthquakes Along the Nankai Trough
- Max Wyss
Published Online: 3 APR 2013
Copyright 1991 American Geophysical Union.
Evaluation of Proposed Earthquake Precursors
How to Cite
Sato, H. (1991) Case 16: Precursory Changes Before the Nankai Earthquake of 1946, in Some Precursors Prior to Recent Great Earthquakes Along the Nankai Trough, in Evaluation of Proposed Earthquake Precursors (ed M. Wyss), American Geophysical Union, Washington, D. C.. doi: 10.1029/SP032p0084
- Published Online: 3 APR 2013
- Published Print: 1 JAN 1991
Print ISBN: 9780875907840
Online ISBN: 9781118667873
- Earthquake prediction—Evaluation
To get suggestions for the researches of earthquake prediction in Tokai district, short-term precursors prior to the recent great earthquakes along the Nankai trough are investigated here. The anomalous tilt of the ground had been observed several hours before the occurrence of the Tonankai earthquake by a leveling party surveying in the Tokai district. The party said also that they recognized with a level unusual quakes of the ground just before the earthquake. It is interesting that the similar phenomena were reported by two survey parties in China.
From the analysis of hourly value of tidal records, precursory land uplift prior to the Nankai earthquake was recognized in the southwest coast of Shikoku. Although the reliability of that uplift was not so high, another precursory phenomena, abnormal changes in the ground water, had occurred in several wells in the area. It is, therefore, probable that there occurred significant changes in the crustal stress and strains prior to the earthquake.
It is noteworthy that those precursors were observed in the areas near the boundary of the focal regions of the earthquakes.