Geophysical Study of the Clear Lake Region, California
Title | Geophysical Study of the Clear Lake Region, California PDF eBook |
Author | Rodger Hale Chapman |
Publisher | |
Pages | 40 |
Release | 1975 |
Genre | Geomagnetism |
ISBN |
Geophysical Study of the Clear Lake Region, California
Title | Geophysical Study of the Clear Lake Region, California PDF eBook |
Author | |
Publisher | |
Pages | |
Release | 1975 |
Genre | |
ISBN |
Results of geophysical studies in the Clear Lake region of California, north of San Francisco, have revealed a prominent, nearly circular negative gravity anomaly with an amplitude of more than 25 milligals (mgal) and an areal extent of approximately 250 square miles and, in addition, a number of smaller positive and negative anomalies. The major negative gravity anomaly is closely associated with the Clear Lake volcanic field and with an area characterized by hot springs and geothermal fields. However, the anomaly cannot be explained by mapped surface geologic features of the area. Aeromagnetic data in the Clear Lake region show no apparent correlation with the major negative gravity anomaly; the local magnetic field is affected principally by serpentine. An electrical resistivity low marks the central part of the gravity minimum, and a concentration of earthquake epicenters characterizes the Clear Lake volcanic field area. The primary cause of the major negative gravity anomaly is believed to be a hot intrusive mass, possibly a magma chamber, that may underlie the Clear Lake volcanic field and vicinity. This mass may serve as a source of heat for the geothermal phenomena in the area. Other smaller gravity anomalies in the Clear Lake region are apparently caused by near-surface geologic features, including relatively dense units of the Franciscan Formation and less dense Cenozoic sedimentary and volcanic rock units.
Research in the Geysers-Clear Lake Geothermal Area, Northern California
Title | Research in the Geysers-Clear Lake Geothermal Area, Northern California PDF eBook |
Author | |
Publisher | |
Pages | 272 |
Release | 1981 |
Genre | Geology |
ISBN |
Geomorphic History of Clear Lake, California
Title | Geomorphic History of Clear Lake, California PDF eBook |
Author | Carroll Ann Hodges |
Publisher | |
Pages | 390 |
Release | 1966 |
Genre | Geology |
ISBN |
Proceedings
Title | Proceedings PDF eBook |
Author | |
Publisher | |
Pages | 740 |
Release | 1976 |
Genre | Geothermal engineering |
ISBN |
Geological Survey Professional Paper
Title | Geological Survey Professional Paper PDF eBook |
Author | |
Publisher | |
Pages | 858 |
Release | 1982 |
Genre | Geology |
ISBN |
List of U.S. Geological Survey Geologic and Water-supply Reports and Maps for California
Title | List of U.S. Geological Survey Geologic and Water-supply Reports and Maps for California PDF eBook |
Author | Geological Survey (U.S.) |
Publisher | |
Pages | 476 |
Release | 1987 |
Genre | California |
ISBN |