Review of Evidence on the Potential for Major Earthquakes and Volcanism in the Long Valley-Mono Craters-White Mountains Regions of Eastern California

Hill, David P.; Wallace, Robert E.; Cockerham, Robert S.

doi:10.1007/978-94-017-2738-9_21

Cited by 11 publications

(11 citation statements)

References 30 publications

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“…Geology of Long Valley caldera and Mono‐Inyo rhyolite domes [after Bailey , 1982; Hill et al , 1985]. S h directions within the caldera are from Moos and Zoback [1993].…”

Section: Examples Of Caldera Collapse In Known Stress Field Environmentsmentioning

confidence: 99%

Effect of stress fields on magma chamber stability and the formation of collapse calderas

Bosworth¹,

Burke

Strecker

2003

Tectonics

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The summits of many of the Earth’s and other planets’ larger volcanoes are occupied by calderas that formed by collapse into an evacuating, underlying magma chamber. These collapse calderas are typically several tens of square kilometers in area and are commonly elliptical in shape. We show that the long axes of late Quaternary collapse calderas in the Kenya rift valley, the western Basin and Range province, the Snake River‐Yellowstone Plateau, and the Iceland rift zone are parallel to the upper crustal minimum horizontal stress direction (Sh) as determined by independent criteria. We suggest that circular magma chambers beneath these volcanoes became elliptical by stress‐induced spalling of their chamber walls, by a mechanism that is analogous to the formation of breakouts in boreholes and tunnels. In breakouts, the hole becomes elongate parallel to the far‐field minimum stress. In the Kenya rift, Late Pleistocene caldera collapse was accompanied by a 45° rotation of Sh and an increase in the magnitude of the maximum horizontal stress (SH). The breakout model predicts increasingly unstable caldera walls under these conditions, a possible explanation for the sudden appearance of so many collapse events in a volcanic setting that had never experienced them before. This mechanism of stress change‐induced collapse may have played a role in other caldera settings.

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“…Geology of Long Valley caldera and Mono‐Inyo rhyolite domes [after Bailey , 1982; Hill et al , 1985]. S h directions within the caldera are from Moos and Zoback [1993].…”

Section: Examples Of Caldera Collapse In Known Stress Field Environmentsmentioning

confidence: 99%

Effect of stress fields on magma chamber stability and the formation of collapse calderas

Bosworth¹,

Burke

Strecker

2003

Tectonics

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“…Because of the earlier ML 6.0 earthquakes in the Mammoth Lakes-Long Valley Caldera area, and the potential for a large earthquake in the White Mountains seismic gap (Hill et al 1985b), a dense network of high-frequency seismic stations was operating in the epicentral region of the Round Valley earthquake prior to the event. The main shock occurred on 1984 November 23 18:08:25.45 UTC at 37.455"N, 118.603"W, and at a depth of 13.4 km.…”

Section: Location and Fault Plane Solution For The Main Shockmentioning

confidence: 99%

“…The aftershock distribution provides important constraints on the 3-D geometry of faulting and further information on the detailed nature of asperities and barriers along the fault. Because of the previous seismic activity in the Bishop-Mammoth Lakes region, and because of the suggested seismic gap in the vicinity of the White Mountains (Hill et al 1985b), a dense network of high gain seismographs was operating in the epicentral area at the time of the Round Valley main shock. This network provided us with an accurately measured (f0.02 s) suite of P-wave arrival times.…”

Section: The R O U N D Valley Aftershock Sequencementioning

confidence: 99%

The 1984 Round Valley, California Earthquake Sequence

Smith¹,

Cockerham²

1988

Geophysical Journal International

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The 1984 November 23 ML 5.8 Round Valley earthquake is one in the.series of moderate earthquakes to have occurred in the Bishop-Mammoth Lakes, California area since 1978. This event and its aftershock sequence are particularly well recorded in that they occurred within a dense, local high frequency seismic network, and strong motion accelerograms, and regional and teleseismic digital seismograms are available for the main shock. We have derived the fault plane solution from the local and regional first motion data, inverted the teleseismic body wave data for the moment tensor solution, and fit regional surface waves for the low frequency moment. Unlike results for several of the earlier moderate events in the Bishop-Mammoth Lakes region, all results for the Round Valley main shock data sets give solutions consistent with left-lateral strike slip faulting on a near vertical N30"E striking plane. The seismic moment of the main shock from the regional surface wave analysis is 7.9 X 101'Nt m. Measurements of the seismic moment from regional surface waves and teleseismic body waves have been converted to spectral level and combined with the acceleration spectra to give a composite source spectrum for the main shock. The spectrum shows a lower corner frequency at 0.2Hz associated with the overall faulting event, and a higher comer frequency at 4.0 Hz which may be associated with the subevents composing the but at a lower slope of w -l between the low and high frequency corners as postulated in models for complex or partial stress drop events.The Round Valley main shock was followed by a widespread and prolonged aftershock sequence. Because of the dense local, high gain permanent seismograph network operated jointly by the University of Nevada-Reno and the United States Geological Survey, accurate locations and fault plane solutions could be determined for the aftershocks beginning immediately after the main shock, and the temporal and spatial growth of the aftershock sequence could be followed in detail. The Round Valley sequence is characterized by the development of two conjugate planes of aftershock activity; one, a near vertical plane striking N30"E associated with the main shock, and another which developed in the first 24 h of activity striking N40"W and dipping 55"NE. This shallow plane conforms to an extension of the Hilton Creek fault postulated by Malcome Clark, and may be the first indication of activity on this major Holocene structure since the recent period of earthquake activity began in 1978. Aftershocks defining the deeper near vertical plane tend to concentrate around the periphery of a 36-49 km2 area which appears to represent the slip surface of the main shock. Relating the seismic moment determined from regional surface waves to this slip area results in an average dislocation of 0.54-0.73 m and a stress drop of 1.5-2.3 MPa. Nearly 800 fault plane solutions for aftershocks were determined. A smaller subset which samples the aftershock zone both spatially and temporally shows that during the initial...

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“…As part of our analysis, we carefully scanned the seismograms for signals of magmatic origin, such as the spasmodic tremor seen at Long Valley during earthquake sequences there in the 1980s [Hill et al, 1985] or the long-period events seen during the 1.989 Mammoth Mountain swarm ]. …”

Section: Review and Analysis Of Seismic Datamentioning

confidence: 99%