Download or read book Acoustic Monitoring of Earthquakes Along the Blanco Transform Fault Zone and Gorda Plate and Their Tectonic Implications written by Robert P. Dziak and published by . This book was released on 1997 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydroacoustic tertiary (T- ) waves are seismically generated acoustic waves that propagate over great distances in the ocean sound channel with little loss in signal strength. Hydrophone recorded T-waves can provide a lower earthquake detection threshold and an improved epicenter location accuracy for oceanic earthquakes than land-based seismic networks. Thus detection and location of NE Pacific ocean earthquakes along the Blanco Transform Fault (BTFZ) and Gorda plate using the U.S. Navy's SOSUS (SOund SUrveillance System) hydrophone arrays afford greater insight into the current state of stress and crustal deformation mechanics than previously available. Acoustic earthquake information combined with bathymetry, submersible observations, earthquake source-parameter estimates, petrologic samples, and water-column chemistry renders a new tectonic view of the southern Juan de Fuca plate boundaries. Chapter 2 discusses development of seismo-acoustic analysis techniques using the well-documented April 1992 Cape Mendocino earthquake sequence. Findings include a hydrophone detection threshold estimate (M~2.4), and T-wave propagation path modeling to approximate earthquake acoustic source energy. Empirical analyses indicate that acoustic energy provides a reasonable magnitude and seismic moment estimate of oceanic earthquakes not detected by seismic networks. Chapters 3 documents a probable volcanogenic T-wave event swarm along a pull-apart basin within the western BTFZ during January 1994. Response efforts yielded evidence of anomalous water-column 3He concentrations, pillow-lava volcanism, and the first discovery of active hydrothermal vents along an oceanic fracture zone. Chapter 4 discusses the detection of a NE-SW trending microearthquake band along the mid-Gorda plate which was active from initiation of SOSUS recording in August 1991 through July 1992, then abruptly ceased. It is proposed that eventual termination of the Gorda plate seismicity band is due to strain reduction associated with the Cape Mendocino earthquake sequence. Chapter 5 combines bathymetric, hydro-acoustic, seismic, submersible, and gravity data to investigate the active tectonics of the transform parallel Blanco Ridge (BR), along the eastern BTFZ. The BR formation mechanism preferred here is uplift through strike-slip motion (with a normal component) followed by formation and intrusion of mantle-derived serpentinized-peridotite into the shallow ocean crust. The conclusion considers a potential link between the deformation patterns observed along the BTFZ and Gorda plate regions.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1998 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Precise Relative Locations for Earthquakes in the Northeast Pacific Region written by and published by . This book was released on 2015 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report that double-difference methods applied to cross-correlation measured Rayleigh wave time shifts are an effective tool to improve epicentroid locations and relative origin time shifts in remote regions. We apply these methods to seismicity offshore of southwestern Canada and the U.S. Pacific Northwest, occurring along the boundaries of the Pacific and Juan de Fuca (including the Explorer Plate and Gorda Block) Plates. The Blanco, Mendocino, Revere-Dellwood, Nootka, and Sovanco fracture zones host the majority of this seismicity, largely consisting of strike-slip earthquakes. The Explorer, Juan de Fuca, and Gorda spreading ridges join these fracture zones and host normal faulting earthquakes. Our results show that at least the moderate-magnitude activity clusters along fault strike, supporting suggestions of large variations in seismic coupling along oceanic transform faults. Our improved relative locations corroborate earlier interpretations of the internal deformation in the Explorer and Gorda Plates. North of the Explorer Plate, improved locations support models that propose northern extension of the Revere-Dellwood fault. Relocations also support interpretations that favor multiple parallel active faults along the Blanco Transform Fault Zone. Seismicity of the western half of the Blanco appears more scattered and less collinear than the eastern half, possibly related to fault maturity. We use azimuthal variations in the Rayleigh wave cross-correlation amplitude to detect and model rupture directivity for a moderate size earthquake along the eastern Blanco Fault. Lastly, the observations constrain the seismogenic zone geometry and suggest a relatively narrow seismogenic zone width of 2 to 4 km.
Download or read book Earthquake Information Bulletin written by and published by . This book was released on 1974 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Kinematics of Transrotational Tectonism in the California Transverse Ranges and Its Contribution to Cumulative Slip Along the San Andreas Transform Fault System written by William R. Dickinson and published by Geological Society of America. This book was released on 1996-01-01 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summaries of Technical Reports Volume X written by and published by . This book was released on 1980 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oceans 2003 written by and published by . This book was released on 2003 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Earthquake Relocations Along the Blanco Tranform Fault Zone written by Herbert E. Larsen (III.) and published by . This book was released on 1997 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Relationship Between Fault Zone Complexity and Earthquake Source Properties written by Arthur Lawrence Lerner-Lam and published by . This book was released on 1993 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Unveiling Active Faults Multiscale Perspectives and Alternative Approaches Addressing the Seismic Hazard Challenge written by Federica Ferrarini and published by Frontiers Media SA. This book was released on 2021-09-24 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Loma Prieta Earthquake written by United States. Congress. House. Committee on Science, Space, and Technology. Subcommittee on Science, Research, and Technology and published by . This book was released on 1990 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preliminary Assessment of Long term Probabilities for Large Earthquakes Along Selected Fault Segments of the San Andreas Fault System California written by Allan Lindh and published by . This book was released on 1983 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geologic Evidence for Triggered Slip on the Calaveras Fault During the Magnitude 7 1 Loma Prieta Earthquake of October 17 1989 written by Patrick H. McClellan and published by . This book was released on 1989 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Planetary Tectonics written by Thomas R. Watters and published by Cambridge University Press. This book was released on 2010 with total page 531 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is an essential reference volume that surveys tectonic landforms on solid bodies throughout the Solar System.
Download or read book Proceedings of the Symposium on the New Madrid Seismic Zone written by Geological Survey (U.S.) and published by . This book was released on 1984 with total page 950 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seismicity Crustal Structure and Tectonics Near the Northern Termination of the San Andreas Fault written by John Stafford Knapp and published by . This book was released on 1982 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book National Earthquake Hazards Reduction Program Summaries of Technical Reports Volume XXX written by and published by . This book was released on 1990 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:
