Seismic Reflection Survey In The Geothermal Field Of The Rotorua Caldera, New Zealand
Journal Article: Seismic Reflection Survey In The Geothermal Field Of The Rotorua Caldera, New Zealand
AbstractA seismic reflection survey was conducted in the southern part of the Rotorua geothermal field (New Zealand). Seismic records contain strong environmental noise attributed to traffic, a severe reverberation and a strong ground roll. Geothermal conditions, including gas, steam pockets and warm highly altered rocks, strongly attenuate the high frequency component of the seismic signal. Comprehensive data processing yielded seismic sections which show evidence of lateral stratigraphic continuity, and normal faulting. Geological structures were interpreted along the two profiles to a depth of about 300 m. A seismic image of the Mamaku Ignimbrite is obtained and appears to show normal faulting. Depth of the top of the Mamaku Ignimbrite corroborates data from boreholes. Thickness of the ignimbrite sheet may reach 280 m near Rotorua City. It is suggested that the Rotorua caldera boundary is not a single fault but a fault zone consisting of at least 4 faults. The displacement on any one fault is no greater than 30 m. The near surface cold-warm thermal boundary, at the northern boundary of the Whakarewarewa thermal area, is also shown in the seismic section.
- Geoffroy Lamarche
- Published Journal
- Geothermics, Date Not Provided
- Not Provided
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Geoffroy Lamarche. . Seismic Reflection Survey In The Geothermal Field Of The Rotorua Caldera, New Zealand. Geothermics. (!) .