title: Abnormal p-wave delays in the geysers--clear lake geothermal area, california.
abstract: Large teleseismic delays, exceeding 1 second, are found near Mount Hannah in the Clear Lake volcanic field and in the steam-production area at The Geysers. The delays are superimposed on a general delay field of about 0.5 second extending over the volcanic rocks and the steam reservoir. It is postulated that a magma chamber under the surface volcanic rocks with a core of severely molten rock beneath Mount Hannah and a highly fractured steam reservoir probably underlain by partially molten rock at The Geysers are responsible for the observed delays. Both zones extend to depths of 20 kilometers or more.
authors.forename: H M
authors.initials: HM
authors.lastname: Iyer
authors.forename: D H
authors.initials: DH
authors.lastname: Oppenheimer
authors.forename: T
authors.initials: T
authors.lastname: Hitchcock