Fluid‐driven seismicity in a stable tectonic context: The Remiremont fault zone, Vosges, France

Abstract

Some relocated seismic events, which have small magnitudes (ML < 4.8), are found to align along a 40 km‐long fault zone flanking the southern Vosges Massif to the west. It joins to the south with the epicentral area of the historical 1682 earthquake (Io = VIII MSK). The Remiremont cluster was preceded by a period of seismic coalescence and triggered outward of bilateral seismic migration. The 1984 seismic crisis developed along a well defined 3 km‐long vertical plane. In both cases, migration rates of the order of 5–10 km/yr over 30 km‐long distances are determined. This pattern requires some mechanism of stress interaction which must act over distances of the order of 1 to 20 km within years. Given the low tectonic activity and the magnitudes of the events the stress transfer cannot result from co‐seismic elastic loading or from transient strain at depth. We suggest that the seismic activity reflect rupture of asperities driven by fluid‐flow in a zone of relatively high permeability.