Fault Plane Solutions and the State of Stress in New England

Graham, T.; Chiburis, E. F.

doi:10.1785/gssrl.51.2.3

Cited by 6 publications

(4 citation statements)

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“…3. Recent focal mechanisms for this zone (Graham, 1978;Pulli and Toksoz, 1980) are sufficiently different that they do not necessarily support the notion of uniform west-northwest-trending compressive regime but rather suggest a complex stress pattern along coastal New England.…”

Section: Description Of Individual Source Zonesmentioning

confidence: 96%

Summary of workshops concerning regional seismic source zones of parts of the conterminous United States, convened by the U.S. Geological Survey, 1979-1980, Golden, Colorado

Thenhaus¹,

McKeown²,

Bucknam³

et al. 1983

Circular

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Workshops were convened by the U.S. Geological Survey to obtain the latest information and concepts relative to defining seismic source zones for five regions of the United States. The zones, with some modifications, have been used in preparation of new national probabilistic ground motion hazard maps by the U.S. Geological Survey. The five regions addressed are the Great Basin, the Northern Rocky Mountains, the Southern Rocky Mountains, the Central Interior, and the northeastern United States. Discussions at the workshops focussed on possible temporal and spatial variations of seismicity within the regions, latest ages of surface-fault displacements, most recent uplift or subsidence, geologic structural provinces as they relate to seismicity, and speculation on earthquake causes. Within the Great Basin region, the zones conform to areas characterized by a predominance of faults that have certain ages of latest surface displacements. In the Northern and Southern Rocky Mountain regions, zones primarily conform to distinctive structural terrane. In the Central Interior, primary emphasis was placed on an interpretation of the areal distribution of historic seismicity, although geophysical studies in the Reelfoot rift area provided data for defining zones in the New Madrid earthquake area. An interpretation of the historic seismicity also provided the basis for drawing the zones of the New England region. Estimates of earthquake maximum magnitudes and of recurrence times for these earthquakes are given for most of the zones and are based on either geologic data or opinion.

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Section: Description Of Individual Source Zonesmentioning

confidence: 96%

Summary of workshops concerning regional seismic source zones of parts of the conterminous United States, convened by the U.S. Geological Survey, 1979-1980, Golden, Colorado

Thenhaus¹,

McKeown²,

Bucknam³

et al. 1983

Circular

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“…The coastal New England region southeast of the Appalachian Mountain highland also experiences small earthquakes that indicate generally northeasterly trending reverse faulting. Of the 18 earthquakes ranging from eastern Connecticut to Maine studied by Graham and Chiburis (1980), 5 of the 7 with reasonably good focal-mechanism solutions have subhorizontal pressure axes and north-to northeast-striking reverse focal mechanisms. For the two exceptions, in Rhode Island and southern New Hampshire, Yang and Aggarwal (1981) present focal-mechanism solutions with subhorizontal pressure axes and northeast-striking reverse focal mechanisms.…”

Section: Seismicitymentioning

confidence: 99%

Regenerate faults of small Cenozoic offset as probable earthquake sources in the southeastern United States

Wentworth¹,

Mergner-Keefer²

1981

Open-File Report

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“…This is consistent with the regional seismic character. Graham & Chiburis (1980) have investigated the focal mechanisms of several events located within 100km of Conway to the south and east and proposed largely thrust solutions with p-axes scattering about east-west orientation. We note that this corresponds to the orientation of the grain plane of the granite (Plumb, Engelder & Yale 1984) which we would expect to control fracture orientation in a…”

Section: Implication For the State-of-stress At The Redstone Sitementioning

confidence: 99%

An analysis of horizontal fracture initiation during hydrofrac stress measurements in granite at North Conway, New Hampshire

Evans¹,

Scholz²,

Engelder³

1988

Geophysical Journal International

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S U M M A R YThe in-situ state of stress was investigated using the hydro-fracturing technique in a cored, borehole in granite at North Conway, New Hampshire, USA. A total of 21 successful tests were made in fracture-free intervals to a depth of 579m. Of the 18 tests in which oriented impressions were taken of induced fractures, 16 were found to be sub-horizontal. Laboratory and finite element simulations show that these fractures could not have been a result of stresses induced by the packer system. Although a conventional analysis in which the borehole wall is assumed to be a smooth continuum would not admit the possibility of horizontal fracturing, we present a simple analysis, based on the experimental result of Jaeger (1963) and the theoretical work of Haimson (1968), that shows that if the fluid intrudes micro-cracks in the borehole wall, horizontal fractures can be initiated where the least horizontal stress is only modestly greater than the vertical stress. For rocks of microdarcy permeability the wellbore pressure must be raised to breakdown levels in less than ten seconds if the effect is to be suppressed.The shut-in pressures provided an unusual opportunity to measure the vertical stresses. The results show that the vertical stress closely followed the calculated overburden to a depth of 400 m. Three measurements below 415 m, however, yielded vertical stresses which are distinctively sub-lithostatic.

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Fault Plane Solutions and the State of Stress in New England

Cited by 6 publications

References 0 publications

Summary of workshops concerning regional seismic source zones of parts of the conterminous United States, convened by the U.S. Geological Survey, 1979-1980, Golden, Colorado

Summary of workshops concerning regional seismic source zones of parts of the conterminous United States, convened by the U.S. Geological Survey, 1979-1980, Golden, Colorado

Regenerate faults of small Cenozoic offset as probable earthquake sources in the southeastern United States

An analysis of horizontal fracture initiation during hydrofrac stress measurements in granite at North Conway, New Hampshire

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