Proceedings of the 6th New Zealand Geothermal Workshop 1985. Seismic monotoring during a cold water injection experiment, Wairakei geothermal field : preliminary results. New Zealand Geothermal Workshop [7-9 Nov. 1984, New Zealand].

Sherburn, S.

[1984]

171
CIENA

0-86869-056-2

A microearthquake survey showed that induced seismic activity occurred during cold water injection tests at Wairakei Geothermal field. Over a six week period more than 120 microearthquakes were recorded; 90 of these occured during the nine days of injection tests. No simple correlation between the occurrence of seismic activity and rate of injection, well head pressure, or step increases in injectivity was observed. Nineteen microearthquakes were located; their epicentres having a roughly elliptical distribution with the major axis in a NE-SW direction. Epicentres were up to 3.3 km from the injection site, the more distant occurring outside the field boundary. The observed 'b' value of 0.6 for the microearthquakes is typical of normal tectonic earthquakes.

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NUEVA ZELANDIA; ENERGIA GEOTERMICA; INYECCION DE AGUA; EXPERIMENTOS; SISMOLOGIA; INTERPRETACION SISMICA; ESTUDIOS GEOFISICOS;