The purpose of this study is to develop an empirical
(semi-empirical) regression model with earthquake magnitude
and step change of groundwater level to estimate the extent of
stress influence. The developed model is based on basic data,
which do not contain detailed information for each earthquake
event (e.g., rupture area). The epicenter (or hypocenter) is a basic
earthquake property that represents the main stress source of an
earthquake. The point force model is thus used to represent the
epicenter (or hypocenter) for the earthquake events. A complex
method considering a complicated plane force theory (e.g., dislocation
model) is another possible model. However, the dislocation
model focuses on mechanism description and the equations are
complex. Some parameters and the fault types might not be easily
obtained under an unknown forthcoming earthquake, which is the
main potential application for the proposed model in this study.
Due to the uncertainties of a forthcoming earthquake, the empirical
(semi-empirical) model is adopted to estimate the extent of
stress influence. The concept can be used to estimate the possible
areas of anomalous stress using detected groundwater level variations
and a given earthquake magnitude before an earthquake