INTRAPLATE EARTHQUAKES IN THE SVALBARD ARCHIPELAGO

A small, seismically active region, designated the Heerland seismic zone, has been delineated in the Svalbard archipelago. Over 500 earthquakes in this region, of which nearly 50 were reliably located, were recorded during a 9-week field season in 1977. This zone provides an example of intraplate earthquake activity in continental-type crust no far from an active plate boundary. A large proportion of the located earthquakes suggests a trend with a dominant east-west direction which is 25km or less in length. The orientation of this grouping of epicenters is nearly transverse to all of the major mapped faults and structural trends in that region. A fault plane solution was obtained for one relatively large teleseismically recorded earthquake which was located near the Heerland zone.-Authors