Catalog of earthquakes along the San Andreas fault system in Central California for the year 1974

Lester, F.W.; Meagher, K.L.

doi:10.3133/ofr781010

Cited by 12 publications

(7 citation statements)

References 14 publications

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“…Earthquakes are located with HYPOINVERSE [Klein, 1989] using a homogeneous layered crustal model determined from refraction studies [Catchings, 1983[Catchings, , 1987. For a full discussion of instrumentation and data processing, see Lester and Meagher [1978] and Stewart and O'Neill [1980]. Between 1980 and the September 1988 swarm (see below), only three earthquakes were located in the vicinity of Medicine Lake caldera.…”

Section: Seismicitymentioning

confidence: 99%

Crustal subsidence, seismicity, and structure near Medicine Lake Volcano, California

Dzurisin¹,

Donnelly‐Nolan²,

Evans³

et al. 1991

J. Geophys. Res.

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The pattern of historical ground deformation, seismicity, and crustal structure near Medicine Lake volcano illustrates a close relation between magmatism and tectonism near the margin of the Cascade volcanic chain and the Basin and Range tectonic province. Between leveling surveys in 1954 and 1989 the summit of Medicine Lake volcano subsided 389±43 mm with respect to a reference bench mark 40 km to the southwest (average rate = 11.1±1.2 mm/yr). A smaller survey across the summit caldera in 1988 suggests that the subsidence rate was 15–28 mm/yr during 1988–1989. Swarms of shallow earthquakes (M ≤ 4.6) occurred in the region during August 1978, January–February 1981, and September 1988. Except for the 1988 swarm, which occurred beneath Medicine Lake caldera, most historical earthquakes were located at least 25 km from the summit. The spatial relation between subsidence and seismicity indicates (1) radially symmetric downwarping of the volcano's summit and flanks centered near the caldera and (2) downfaulting of the entire edifice along regional faults located 25–30 km from the summit. We propose that contemporary subsidence, seismicity, and faulting are caused by (1) loading of the crust by more than 600 km3 of erupted products plus a large volume of mafic intrusives; (2) east‐west extension in the western Basin and Range province; and, to a lesser extent, (3) crystallization or withdrawal of magma beneath the volcano. Thermal weakening of the subvolcanic crust by mafic intrusions facilitates subsidence and influences the distribution of earthquakes. Subsidence occurs mainly by aseismic creep within 25 km of the summit, where the crust has been heated and weakened by intrusions, and by normal faulting during episodic earthquake swarms in surrounding, cooler terrain.

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Section: Seismicitymentioning

confidence: 99%

Crustal subsidence, seismicity, and structure near Medicine Lake Volcano, California

Dzurisin¹,

Donnelly‐Nolan²,

Evans³

et al. 1991

J. Geophys. Res.

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“…The shocks with the smallest magnitudes are found in the Central California catalogue prepared by the US Geological Survey, called USGS in this paper. In its raw form it spans the years [1969][1970][1971][1972][1973][1974][1975] and includes earthquakes with magnitudes as low as zero (Lester & Meagher 1978, and references therein).…”

Section: The Cataloguesmentioning

confidence: 99%

Spatial distribution of earthquakes: the two-point correlation function

Kagan

Knopoff

1980

Geophysical Journal International

360

201

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Summary. The distribution of distances between pairs of earthquake epicentres and hypocentres has been determined for four local and two world‐wide catalogues. These spatial correlation functions shows that the number of events per unit volume at distance R from any earthquake is proportional to R‐α, where a is close to 1.0 for shallow earthquakes and increases to 1.5 or possibly larger for deeper events. This distribution of earthquakes is independent of magnitude and independent of the dimensions of the region under consideration. These results place limits on possible models of earthquake fault geometries.

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“…Catalogs for the first, second, third, and fourth quarters of 1972 and the first, second, third and fourth quarters of 1973 have been prepared by others (1972a, b, 1973b, andI974a andb), by Bufe and others (1975), and by Lester and others (1976a and b). Catalogs for the years 1974, 1975 and 1976 and the first, second, third and fourth quarters of 1977 have been prepared by Lester and Meagher (1978), by 1979) by Lester (1980a and1980b), by Marks and Fluty (1981), and by Fluty and Marks (1981). The basic data contained in these catalogs provide a foundation for further studies.…”

Section: Illustrationsmentioning

confidence: 99%

Catalog of earthquakes along the San Andreas fault system in Central California for the year 1974

Cited by 12 publications

References 14 publications

Crustal subsidence, seismicity, and structure near Medicine Lake Volcano, California

Crustal subsidence, seismicity, and structure near Medicine Lake Volcano, California

Spatial distribution of earthquakes: the two-point correlation function

Catalog of earthquakes along the San Andreas fault system in Central California, January-June 1978

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