Publications

Five geodetic arrays (10 to 40 km aperture) located along the San Andreas fault have been surveyed frequently (several times in most years) over the 1980–1991 interval to detect possible fluctuations in the deformation rate. In each survey of an array the distances between the same four to seven pairs of geodetic monuments were measured. The distances measured (with corresponding standard deviatio

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Temperatures within the main vapor-dominated steam reservoir at The Geysers geothermal field generally are in the range 238°C to 244°C. A few deep wells in the northwestern part of the field have penetrated beneath this reservoir into a second vapor-dominated reservoir where temperatures are >315°C, while vapor pressure remains nearly constant at about 35.9 bars (Walters et al., 1992). Vapor-domin

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This report releases the results of selected chemical analyses by the USGS of fluids collected from geothennal power production wells at the Cerro Prieto Geothennal Field, Mexico. Cerro Prieto, the world's largest producing hot-water geothennal field, is located 32 km southeast of Mexicali, Baja California. Comision Federal de Electricidad de Mexico (CFE) gave permission for, and assisted in, samp

Ash Mountain, South Tuya, and Tuya Butte are three small basaltic volcanoes in the Stikine volcanic belt of northern British Columbia. The volcanoes rise 700, 500, and 400 m above their bases and are about 3.2, 1.6, and 2.6 km3 in volume, respectively. They began eruptive activity under several hundred meters of overlying glacial ice, or water in an ice‐impounded lake, and undegassed pillow lava w

This map shows the geology of the central and eastern parts of the Cascade Range in northern Oregon. The Quaternary andesitic stratovolcano of Mount Hood dominates the northwest quarter of the quadrangle, but nearly the entire area is underlain by arc-related volcanic and volcaniclastic rocks of the Cascade Range. Most stratigraphic units were emplaced since middle Miocene time, and all are Oligoc

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During 1994, the Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, or false alarms at nine volcanic centers-- Mount Sanford, Iliamna, the Katmai group, Kupreanof, Mount Veniaminof, Shishaldin, Makushin, Mount Cleveland and Kanaga (table 1). Of these volcanoes, AVO has a real time, continuously recording seismic network only at Iliamna, which is located in the Cook Inlet

No abstract available.