Case 15: Anomalous Strain Response to Rainfall in Relation to Earthquake Occurrence in the Tokai Area, Japan,
- Max Wyss
Published Online: 3 APR 2013
Copyright 1991 American Geophysical Union.
Evaluation of Proposed Earthquake Precursors
How to Cite
Yamauchi, T. (1991) Case 15: Anomalous Strain Response to Rainfall in Relation to Earthquake Occurrence in the Tokai Area, Japan,, in Evaluation of Proposed Earthquake Precursors (ed M. Wyss), American Geophysical Union, Washington, D. C.. doi: 10.1029/SP032p0078
- Published Online: 3 APR 2013
- Published Print: 1 JAN 1991
Print ISBN: 9780875907840
Online ISBN: 9781118667873
- Earthquake prediction—Evaluation
The effect of rainfall on crustal strain at the Mikawa Crustal Movement Observatory, central Japan, was studied in detail with a data set from January 1974 through December 1984. Changes in crustal strain caused by rainfall were successfully simulated by a tank model, in which the crustal strain is given as a nonlinear function of precipitation and time. The simulation error was usually less than 10%, but occasionally it became larger. There were anomalies of two kinds: 1) a change in spatial distribution of strains in the observation tunnel; 2) an increase in simulation error for the rainfall effect. These anomalous responses seem to be related to the occurrence of nearby earthquakes within a particular area around the observatory. The logarithmic duration time of anomaly was roughly proportional to the earthquake magnitude. Data from the past eleven years indicate that about 50% of M>3.5 earthquakes in the area were preceded by anomalous strain responses if they occurred after rain. The change in strain response to rainfall at this observatory could be a precursor of a nearby earthquake.