Fluid activities overpressure

Compared to tectonic earthquakes at the plate boundaries, the intraplate earthquake swarm areas miss the plate motion that could periodically bring the fault to failure. Recent studies have tried to understand the possible triggering mechanisms by probing/imaging anomalous crustal structures within seismic swarms linked to fluids (e.g., Lin and Shearer 2009 Kato et al. 2010). It is assumed that afluid overpressure builds up and acts as a triggering mechanism of earthquake swarms. The subsequent swarm activity is then probably driven both by the fluid flow along the fault zone and stress transfer from previous earthquakes. This idea is based on characteristic features of earthquake swarms that help us to disclose their background mechanisms. 

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