Three-dimensional p-velocity structure of the summit caldera of Newberry Volcano, Oregon

Stauber, Douglas A.; Iyer, N.M.; Mooney, Walter D.; Dawson, Phillip B.

doi:10.2172/6314574

Cited by 7 publications

(7 citation statements)

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“…We use the NeHT method to resolve seismic velocity structures as small as 1 to 2 km across in a three-dimensional volume of the upper crust beneath the summit caldera and east flank of Medicine Lake volcano. Stauber et al [1985] performed a similar experiment at Newberry volcano in central Oregon (Figure 1 own below. Finally, we present an extension of the NeHT method for imaging seismic attenuation structure using a •t* method similar to the one described by Young and Ward [1981] and discuss the types of materials that can produce both the velocity and attenuation features observed.…”

Section: Previous Geophysical Work Has Shown That Medicine Lake Volcamentioning

confidence: 99%

“…This constant is removed in the subsequent processing described below. This picking method also was employed in the Newberry volcano NeHT experiment by Stauber et al [1985]. The repeatability of these picks is about _+0.01 s, substantially better th• can be obtained for first arrivals (especially refracted ones) by conventional methods.…”

Section: Compressional Wave Velocity Structurementioning

confidence: 99%

“…Thus the feature is similar in depth, volume, and magnitude to the feature observed beneath Newberry volcano's caldera by Stauber et al [1985]. It also partly underlies the high-velocity lens of layer 2 (Figure 7) and therefore is not likely to be caldera-filling collapse breccia or similar low-velocity subsolidus material.…”

Section: Thus Sincementioning

confidence: 99%

“…This feature at Newberry volcano is a ring or cylinder structure underlying well-mapped caldera ring faults. It is thought to be cone sheets intruding these faults and partly controlling hydrothermal Circulation in about the upper 1 km of the volcano [Stauber et al, 1985;Samreel et al, 1988]. At Medicine Lake volcano, the same structure gives no hint of a ring shape and underlies a much less pronounced caldera.…”

Section: The Central Caldera Low-velocity Anomaly In Layer 3 Subsmildmentioning

confidence: 99%

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Active high‐resolution seismic tomography of compressional wave velocity and attenuation structure at Medicine Lake Volcano, Northern California Cascade Range

Evans¹,

Zucca²

1988

J. Geophys. Res.

119

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We determine compressional wave velocity and attenuation structures for the upper crust beneath Medicine Lake volcano in northeast California using a high‐resolution active source seismic tomography method. Medicine Lake volcano is a basalt through rhyolite shield volcano of the Cascade Range, lying east of the range axis. The Pg wave from eight explosive sources which has traveled upward through the target volume to a dense array of 140 seismographs provides 1‐ to 2‐km resolution in the upper 5 to 7 km of the crust beneath the volcano. The experiment tests the hypothesis that Cascade Range volcanoes of this type are underlain only by small silicic magma chambers. We image a low‐velocity low‐Q region not larger than a few tens of cubic kilometers in volume beneath the summit caldera, supporting the hypothesis. A shallower high‐velocity high‐density feature, previously known to be present, is imaged for the first time in full plan view; it is east‐west elongate, paralleling a topographic lineament between Medicine Lake volcano and Mount Shasta. This lineament is interpreted to be the result of an old crustal weakness now affecting the emplacement of magma, both on direct ascent from the lower crust and mantle and in migration from the shallow silicic chamber to summit vents. Differences between this high‐velocity feature and the equivalent feature at Newbeny volcano, a volcano in central Oregon resembling Medicine Lake volcano, may partly explain the scarcity of surface hydrothermal features at Medicine Lake volcano. A major low‐velocity low‐Q feature beneath the southeast flank of the volcano, in an area with no Holocene vents, is interpreted as tephra, flows, and sediments from the volcano deeply ponded on the downthrown side of the Gillem fault, a normal fault mapped at the surface north of the volcano. A high‐Q normal‐velocity feature beneath the north rim of the summit caldera may be a small, possibly hot, subsolidus intrusion. A high‐velocity low‐Q region beneath the eastern caldera may be an area of boiling water between the magma chamber and the ponded east flank material. These structural data are useful both for understanding Cascade Range volcanism and for geothermal development in progress on the volcano.

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Section: Previous Geophysical Work Has Shown That Medicine Lake Volcamentioning

confidence: 99%

Section: Compressional Wave Velocity Structurementioning

confidence: 99%

Section: Thus Sincementioning

confidence: 99%

Section: The Central Caldera Low-velocity Anomaly In Layer 3 Subsmildmentioning

confidence: 99%

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Active high‐resolution seismic tomography of compressional wave velocity and attenuation structure at Medicine Lake Volcano, Northern California Cascade Range

Evans¹,

Zucca²

1988

J. Geophys. Res.

119

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“…Additional research drilling (see Figure 2) by Sandia National Laboratories (Sandia RDO-1 [Black et al, 1984] Fitterman, 1983;Fitterman and Neev, 1985;Fitterman et al, 1985, this issue], determination of the regional crustal velocity structure [Catchings and Mooney, this issue], and imaging of the velocity structure below Newberry Volcano using teleseismic and explosive sources [Stauber et al, 1985, zones may be a single fault zone, the middle part of which is buried by Newberry Volcano.…”

Section: Paper Number 8b1139mentioning

confidence: 99%

Overview of the structure and geothermal potential of Newberry Volcano, Oregon

Fitterman¹

1988

J. Geophys. Res.

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Evidence from a broad range of geological and geophysical investigations of Newberry Volcano in central Oregon suggests the presence of a small magma body beneath the summit caldera. Drilling has encountered temperatures indicative of a hydrothermal system above the hypothesized magma body. On the basis of hydrothermal mineralogy the temperature of the hydrothermal system is at or near its maximum value, indicating that the hydrothermal system is young. Basaltic underplating is postulated to replenish the magma body. The results of interdisciplinary studies at Newberry Volcano document that young, silicic volcanism in the Cascade Range can have geothermal potential. These results should be applied with caution to the rest of the Cascade Range because of the strong influence of Basin and Range extensional tectonics on Newberry Volcano's style of volcanism.

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Seismological Detection and Delineation of Magma Chambers Beneath Intraplate Volcanic Centers in Western U.S.A.

Iyer

1988

Modeling of Volcanic Processes

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Three-dimensional p-velocity structure of the summit caldera of Newberry Volcano, Oregon

Cited by 7 publications

References 0 publications

Active high‐resolution seismic tomography of compressional wave velocity and attenuation structure at Medicine Lake Volcano, Northern California Cascade Range

Active high‐resolution seismic tomography of compressional wave velocity and attenuation structure at Medicine Lake Volcano, Northern California Cascade Range

Overview of the structure and geothermal potential of Newberry Volcano, Oregon

Seismological Detection and Delineation of Magma Chambers Beneath Intraplate Volcanic Centers in Western U.S.A.

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