Influence of near and intermediate fields on magnitude and seismic moment estimation for anthropogenic events
摘要
Routine analysis of source parameters is mainly based on the assumption that stations are located in the far field, which is valid for most measurement conditions of natural seismicity. The study aims to examine the validity of this assumption for anthropogenic seismicity characterized by shallower earthquakes and smaller distances of stations from seismic sources. Data from three real cases were studied: reservoir-triggered seismicity in Vietnam, copper mining-induced seismicity in Poland and geothermal field The Geysers. The influence of the intermediate and near fields on the values previously used to calculate source parameters was assessed. The results indicate the need to improve tools employed so far. It is especially significant in the seismicity induced by copper mines and geothermal field, even when surface stations monitor the seismicity. These effects are less important in the case of the tested seismicity in Song Tranh 2 but should not be neglected.