Publication Citation

USGS Series Open-File Report
Report Number 79-1691
Title Seismic studies at the Mt. Hood Volcano, northern Cascade Range, Oregon
Edition -
Language ENGLISH
Author(s) Green, Susan Molly; Weaver, Craig S.; Iyer, Hariharaiyer Mahadeva
Year 1979
Originating office
USGS Library Call Number (200) R29o no.79-1691
Physical description 27 leaves, [13] leaves of plates :ill., maps ;27 cm.; (40 p. - PGS)
ISBN

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Abstract

A sixteen station telemetered seismic network was established in the Mt. Hood, Oregon area to monitor local seismicity and to study crustal and upper mantle structure. The network was in operation 13 months, and recorded 10 local earthquakes, 25 regional events, and 300 teleseisms. A series of construction blasts were recorded and used to define an average upper crustal velocity of 5.4 km/s in the region. All local earthquakes occurred beneath Mt. Hood at shallow depths and roughly define a zone striking north-northwest beneath the mountain. The largest earthquake was a magnitude 3.4 event which had a strike-slip focal mechanism. The other events had magnitudes (ML) less than 2.0. P-wave travel time residuals from teleseismic events show a 0.5 second decrease in travel time from east to west across the Cascade Range. No travel time anomalies are associated directly with Mt. Hood.