| Abstract: | Two reversed seismic-refraction profiles were recorded between Los Angeles and San Francisco in 1961. The three shotpoints were located in Santa Monica Bay, offshore near San Francisco, and at Camp Roberts, about halfway between Los Angeles and San Francisco. The velocity of Pg along these profiles is 6.1 ± 0.1 km/sec, with possible exceptions near San Francisco and near Los Angeles, where the scatter in the arrival times indicates complex near-surface velocity variations. The velocity of Pn between Los Angeles and Camp Roberts is 8.2 ± 0.1 km/sec, and between Camp Roberts and San Francisco 8.0 ± 0.2 km/sec. There is no indication of an intermediate crustal layer in the traveltimes of first arrivals. Computed depths to the Mohorovicic discontinuity, if the crust consists of a single layer, are: 35 km at Los Angeles, 23 km at Camp Roberts, and 23 km at San Francisco. Refractions from crustal layers of intermediate velocity need not appear as first arrivals, and in the extreme, the depth to the Mohorovicic discontinuity may be one-third greater than the thickness of a one-layer crust. |
| Genre: | USGS Unnumbered Series |
| ProdID: | 70039278 |
| Citation Author: | Healy, J. H. |
| Citation Contributing Office: | Earthquake Science Center |
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| Citation End Page: | 30 |
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| Citation Language: | English |
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| Citation Number Of Pages: | 40 |
| Citation Online Only Flag: | Y |
| Citation Phsyical Description: | 30 p. |
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| Citation Public Comments: | In cooperation with the Defense Advanced Research Projects Agency |
| Citation Publisher: | U.S. Geological Survey |
| Citation Series: | Crustal Studies Technical Letter |
| Citation Series Code: | |
| Citation Series Number: | 5 |
| Citation Search Results Text: | Crustal structure along the coast of California from seismic-refraction measurements; 1962; USGS Unnumbered Series; 5; Healy, J. H. |
| Citation Start Page: | 1 |
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| Citation Year: | 1962 |
| Type: | citation/reference |
| Text: | Crustal structure along the coast of California from seismic-refraction measurements; 1962; USGS Unnumbered Series; 5; Healy, J. H. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/usgs_thumb.jpg |
| URL (INDEX PAGE): | http://pubs.usgs.gov/misc/tl/0005/ |
| URL (DOCUMENT): | http://pubs.usgs.gov/misc/tl/0005/tl0005.pdf |
| Date Other: | Sun, 1 Jan 2012 12:29 -0600 |
| Publisher: | U.S. Geological Survey |
