Seismotectonics of the Cape Mendocino, California, area

Abstract

Research Article| October 01, 1975 Seismotectonics of the Cape Mendocino, California, area G. W. SIMILA; G. W. SIMILA 1Seismographic Station, Department of Geology and Geophysics, University of California, Berkeley, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar W. A. PEPPIN; W. A. PEPPIN 1Seismographic Station, Department of Geology and Geophysics, University of California, Berkeley, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar T. V. McEVILLY T. V. McEVILLY 1Seismographic Station, Department of Geology and Geophysics, University of California, Berkeley, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Author and Article Information G. W. SIMILA 1Seismographic Station, Department of Geology and Geophysics, University of California, Berkeley, Berkeley, California 94720 W. A. PEPPIN 1Seismographic Station, Department of Geology and Geophysics, University of California, Berkeley, Berkeley, California 94720 T. V. McEVILLY 1Seismographic Station, Department of Geology and Geophysics, University of California, Berkeley, Berkeley, California 94720 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1975) 86 (10): 1399–1406. https://doi.org/10.1130/0016-7606(1975)86<1399:SOTCMC>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation G. W. SIMILA, W. A. PEPPIN, T. V. McEVILLY; Seismotectonics of the Cape Mendocino, California, area. GSA Bulletin 1975;; 86 (10): 1399–1406. doi: https://doi.org/10.1130/0016-7606(1975)86<1399:SOTCMC>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A radio-telemetered network of high-gain seismographs allowed determination of hypocenters for 150 earthquakes with depths of 5 to 30 km in the Cape Mendocino area. Analysis of P- and S-wave arrival times indicates that the region exhibits a Poisson's ratio in excess of 0.3. The pattern of seismicity reveals a diffuse distribution. Composite fault-plane solutions indicate general north-south compression, consistent with generally inferred movements of the Pacific, North American, and Gorda plates. Near the cape, however, the principal compression is oriented roughly northwest-southeast, consistent with Gorda plate motion normal to the ridge. Right-lateral strike-slip movement appears to be the dominant faulting pattern. Thrust-fault mechanisms seen at the continental margin near the cape may reflect late Cenozoic underthrusting at the Gorda plate boundary. East-west cross sections of hypocenters show no indications of an active Benioff zone. These results are consistent with the hypothesis that the San Andreas fault joins the Mendocino fracture zone, which absorbs most of the right-lateral strike-slip motion. The Gorda plate is now deforming near the continental margin, apparently the consequence of transition from thrusting near the cape to right-lateral faulting northward as the mode of accommodation of the relative plate motions. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.