Microseismicity and 3-D Mapping of an Active Geothermal Field, Kilauea Lower East Rift Zone, Puna, Hawaii

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Conference Paper: Microseismicity and 3-D Mapping of an Active Geothermal Field, Kilauea Lower East Rift Zone, Puna, Hawaii

Abstract
The local fault and dike structures in Puna, southeastern Hawaii, are of interest both in terms of electricity productionand volcanic hazard monitoring. The geothermal powerplant at Puna has a 30 MW capacity and is built on a sectionof the Kilauea Lower East Rift Zone that was resurfaced by lava flows as recently as 1955 and 1960.The Puna Borehole Network was established in 2006 inorder to provide detailed seismic data about the Puna geothermal field. The array consists of eight 3-component borehole seismometers. The instrument depths range from 24 to 210 m (80 to 690 ft); five stations with 2 Hz geophones and three with 4.5 Hz geophones. The large majority of events were < M0.5 and occurred at depths between 2 and 3 km. The size, location, and depth of the microearthquakes suggest that power plant activity affects local seismicity. Earthquake depths increase from NE to SW, trending up the rift zone towards the Kilauea summit. Depths also increase from the study area to the SE, consistent with active normal faulting along Kilauea's southflank. Shear wave polarization indicates that the active,fluid-filled fracture system trends SW-NE, consistent with the orientation of the LERZ. Double difference relocation suggests an intersecting network of fractures with both NE and approximately NW trends. 3-D tomographic analyses of P-wave velocity, S-wave velocity, and the Vp/Vs ratio are also presented. An area of anomalously fast P-wave velocity at the relatively shallow depth of 2.5 km may be evidence for a dense, gabbroic intrusion. This intrusion may underlie and be the parent of a body of dacitic melt that was discovered under the geothermal field during drilling.

Authors 
Catherine Lewis Kenedi, Eylon Shalev, Alan Lucas and Peter Malin






Conference 
Proceedings World Geothermal Congress 2010; Bali, Indonesia; 04/2010


Published 
Proceedings World Geothermal Congress 2010;, 2010





DOI 
Not Provided
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Online 
Internet link for [http:// http://www.geothermal-energy.org/pdf/IGAstandard/WGC/2010/1352.pdf Microseismicity and 3-D Mapping of an Active Geothermal Field, Kilauea Lower East Rift Zone, Puna, Hawaii]

Citation

Catherine Lewis Kenedi,Eylon Shalev,Alan Lucas,Peter Malin. 2010. Microseismicity and 3-D Mapping of an Active Geothermal Field, Kilauea Lower East Rift Zone, Puna, Hawaii. In: Proceedings World Geothermal Congress 2010. Proceedings World Geothermal Congress 2010; 04/2010; Bali, Indonesia. (!) : (!) ; p. (!)


Related Geothermal Exploration Activities
Activities (1)


Areas (1)
  1. Kilauea East Rift Geothermal Area
Regions (0)