Publications
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A filter circuit board for the Earthworm Seismic Data Acquisition System
The Earthworm system is a seismic network data acquisition and processing system used by the Northern California Seismic Network as well as many other seismic networks. The input to the system is comprised of many realtime electronic waveforms fed to a multi-channel digitizer on a PC platform. The digitizer consists of one or more National Instruments Corp. AMUX–64T multiplexer boards attached to
Authors
Edward Gray Jensen
Report for explosion and earthquake data acquired in the 1999 Seismic Hazards Investigation of Puget Sound (SHIPS), Washington
This report describes the acquisition, processing, and quality of seismic reflection and refraction data obtained in the Seattle basin, central Puget Lowland, western Washington, in September 1999 during the Seismic Hazards Investigation of Puget Sound (SHIPS). As a sequel to the 1998 SHIPS air gun experiment (also known as 'Wet SHIPS'), the 1999 experiment, nicknamed 'Dry SHIPS,' acquired a 112-k
Authors
Thomas M. Brocher, Thomas L. Pratt, Kate C. Miller, Anne M. Tréhu, Catherine M. Snelson, Craig S. Weaver, Ken C. Creager, Robert S. Crosson, Uri S. ten Brink, Marcos G. Alvarez, Steven H. Harder, Isa Asudeh
SMSIM--Fortran programs for simulating ground motions from earthquakes: Version 2.0.--a revision of OFR 96-80-A
A simple and powerful method for simulating ground motions is based on the assumption that the amplitude of ground motion at a site can be specified in a deterministic way, with a random phase spectrum modified such that the motion is distributed over a duration related to the earthquake magnitude and to distance from the source. This method of simulating ground motions often goes by the name "the
Authors
David M. Boore
Hydrogen defects in α-Al2O3 and water weakening of sapphire and alumina ceramics between 600°C and 1000°C: II. Mechanical properties
Hydrogen impurities in alumina have been introduced by hydrothermal annealing (see part I). In this paper, we report on reductions in the flow strength of α-Al2O3 single crystals and polycrystals associated with hydrogen incorporation. Prior to deformation, α-Al2O3 single crystal and ceramic specimens were annealed in the presence of supercritical water at 850° or 900°C, under 1500 MPa pressure. S
Authors
J. Castaing, A. K. Kronenberg, S. H. Kirby, T. E. Mitchell
Towards policy relevant environmental modeling: contextual validity and pragmatic models
"What makes for a good model?" In various forms, this question is a question that, undoubtedly, many people, businesses, and institutions ponder with regards to their particular domain of modeling. One particular domain that is wrestling with this question is the multidisciplinary field of environmental modeling. Examples of environmental models range from models of contaminated ground water flow
Authors
Scott B. Miles
Three-month performance evaluation of the Nanometrics, Inc., Libra Satellite Seismograph System in the northern California Seismic Network
In 1999 the Northern California Seismic Network (NCSN) purchased a Libra satellite seismograph system from Nanometrics, Inc to assess whether this technology was a cost-effective and robust replacement for their analog microwave system. The system was purchased subject to it meeting the requirements, criteria and tests described in Appendix A. In early 2000, Nanometrics began delivery of various c
Authors
David H. Oppenheimer
Taking the Earth's Pulse
During the past 35 years, scientists have developed a vast network of seismometers that record earthquakes, volcanic eruptions, and nuclear explosions throughout the world. Seismographic data support disaster response, scientific research, and global security. With this network, the United States maintains world leadership in monitoring the greatest natural and technological events that threaten o
Authors
Robert L. Woodward, Harley Mitchell Benz, Kaye M. Shedlock, William M. Brown
Quantifying precambrian crustal extraction: The root is the answer
We use two different methods to estimate the total amount of continental crust that was extracted by the end of the Archean and the Proterozoic. The first method uses the sum of the seismic thickness of the crust, the eroded thickness of the crust, and the trapped melt within the lithospheric root to estimate the total crustal volume. This summation method yields an average equivalent thickness of
Authors
D. Abbott, D. Sparks, C. Herzberg, Walter D. Mooney, A. Nikishin, Y.-S. Zhang
A crustal model of the ultrahigh-pressure Dabie Shan orogenic belt, China, derived from deep seismic refraction profiling
We present a new crustal cross section through the east-west trending ultrahigh-pressure (UHP) Dabie Shan orogenic belt, east central China, based on a 400-km-long seismic refraction profile. Data from our profile reveal that the cratonal blocks north and south of the orogen are composed of 35-km-thick crust consisting of three layers (upper, middle, and lower crust) with average seismic velocitie
Authors
Chun-Yong Wang, Rong-Sheng Zeng, Walter D. Mooney, B. R. Hacker
Timing of paleoearthquakes on the northern Hayward Fault: Preliminary evidence in El Cerrito, California
The Working Group on California Earthquake Probabilities estimated that the northern Hayward fault had the highest probability (0.28) of producing a M7 Bay Area earthquake in 30 years (WGCEP, 1990). This probability was based, in part, on the assumption that the last large earthquake occurred on this segment in 1836. However, a recent study of historical documents concludes that the 1836 earthquak
Authors
J. J. Lienkaemper, D. P. Schwartz, K. I. Kelson, W. R. Lettis, Gary D. Simpson, J. R. Southon, J. A. Wanket, P. L. Williams
Wide-angle seismic recordings from the 1998 Seismic Hazards Investigation of Puget Sound (SHIPS), western Washington and British Columbia
This report describes the acquisition and processing of deep-crustal wide-angle seismic reflection and refraction data obtained in the vicinity of Puget Lowland, the Strait of Juan de Fuca, and Georgia Strait, western Washington and southwestern British Columbia, in March 1998 during the Seismic Hazards Investigation of Puget Sound (SHIPS). As part of a larger initiative to better understand later
Authors
Thomas M. Brocher, Tom Parsons, Ken C. Creager, Robert S. Crosson, Neill P. Symons, George D. Spence, Barry C. Zelt, Philip T.C. Hammer, Roy D. Hyndman, David C. Mosher, Anne M. Tréhu, Kate C. Miller, Uri S. ten Brink, Michael A. Fisher, Thomas L. Pratt, Marcos G. Alvarez, Bruce C. Beaudoin, Keith E. Louden, Craig S. Weaver
Turbidite pathways in Cascadia Basin and Tufts abyssal plain, Part A, Astoria Channel, Blanco Valley, and Gorda Basin
This open-file report was prepared in support of the USGS Earthquake Hazards of Cascadia Project. The primary objective of this phase of the project is to determine recurrence intervals of turbidites in Cascadia basin-floor channel systems and evaluate implications of this event record for the paleoseismic history of the Cascadia subduction zone. The purpose of this study is to determine whether t
Authors
Stephen C. Wolf, Michael R. Hamer