scholarly journals An Improved Method to Determine Coda‐ Q , Earthquake Magnitude, and Site Amplification: Theory and Application to Southern California

2019 ◽  
Vol 124 (1) ◽  
pp. 578-598 ◽  
Author(s):  
W. Wang ◽  
P. M. Shearer
Keyword(s):  
Southern California ◽  
Site Amplification ◽  
Earthquake Magnitude ◽  
Improved Method ◽  
Coda Q

Evaluation of Ground-Motion Models for USGS Seismic Hazard Models Using Near-Source Instrumental Ground-Motion Recordings of the Ridgecrest, California, Earthquake Sequence

2020 ◽  
Vol 110 (4) ◽  
pp. 1517-1529
Author(s):  
Daniel E. McNamara ◽  
Emily L. G. Wolin ◽  
Morgan P. Moschetti ◽  
Eric M. Thompson ◽  
Peter M. Powers ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Southern California ◽  
Epistemic Uncertainty ◽  
Site Amplification ◽  
Earthquake Sequence ◽  
Scoring Method ◽  
Motion Models ◽  
Tectonically Active ◽  
Ground Motion Models

ABSTRACT We evaluated the performance of 12 ground-motion models (GMMs) for earthquakes in the tectonically active shallow crustal region of southern California using instrumental ground-motion observations from the 2019 Ridgecrest, California, earthquake sequence (Mw 4.0–7.1). The sequence was well recorded by the Southern California Seismic Network and rapid response portable aftershock monitoring stations. Ground-motion recordings of this size and proximity are rare, valuable, and independent of GMM development, allowing us to evaluate the predictive powers of GMMs. We first compute total residuals and compare the probability density functions, means, and standard deviations of the observed and predicted ground motions. Next we use the total residuals as inputs to the probabilistic scoring method (log-likelihood [LLH]). The LLH method provides a single score that can be used to weight GMMs in the U.S. Geological Survey (USGS) National Seismic Hazard Model (NSHM) logic trees. We also explore GMM performance for a range of earthquake magnitudes, wave propagation distances, and site characteristics. We find that the Next Generation Attenuation West-2 (NGAW2) active crust GMMs perform well for the 2019 Ridgecrest, California, earthquake sequence and thus validate their use in the 2018 USGS NSHM. However, significant ground-motion residual scatter remains unmodeled by NGAW2 GMMs due to complexities such as local site amplification and source directivity. Results from this study will inform logic-tree weights for updates to the USGS National NSHM. Results from this study support the use of nonergodic GMMs that can account for regional attenuation and site variations to minimize epistemic uncertainty in USGS NSHMs.

κ 0 and Broadband Site Spectra in Southern California from Source Model‐Constrained Inversion

2019 ◽  
Vol 109 (5) ◽  
pp. 1878-1889 ◽  
Author(s):  
Alexis Klimasewski ◽  
Valerie Sahakian ◽  
Annemarie Baltay ◽  
John Boatwright ◽  
Jon B. Fletcher ◽  
...  
Keyword(s):  
Ground Motion ◽  
High Frequency ◽  
Southern California ◽  
Order Approximation ◽  
Site Amplification ◽  
Source Model ◽  
Ground Motion Prediction Equations ◽  
Motion Modeling ◽  
First Order Approximation ◽  
Good Agreement

Abstract Ground‐motion modeling requires accurate representation of the earthquake source, path, and site. Site amplification is often modeled by VS30, the time‐averaged shear‐wave velocity of the top 30 m of the Earth’s surface, though recent studies find that its ability to accurately predict site effects varies. Another measure of the site is κ0, the attenuation of high‐frequency energy near the site (Anderson and Hough, 1984). We develop a novel application of the Andrews (1986) method to simultaneously invert the spectra of 3357 earthquakes in Southern California into source and site components. These earthquakes have magnitudes 2.5–5.72 and were recorded on 16 stations for a total of 52,297 records. We constrain the inversion with an individual earthquake, demonstrating the most Brune‐like shape to preserve the site spectra. We then solve for κ0 site amplification at each station in three frequency bands: 1–6 Hz, 6–14 Hz, and 14–35 Hz. The resulting values of κ0 range from 0.017 s at ANZA station PFO to 0.059 s at ANZA station SND. We compare our results to values of site κ0 from other studies, as well as site residuals from ground‐motion prediction equations. We find good agreement between our site κ0 and previous studies in the region. We find that κ0 and high‐frequency site amplification (14–35 Hz band) correlates well with independent site residuals, making it a good first‐order approximation for the effects of site attenuation or amplification on ground motion.

Temporal Stability of Coda Q-1 in Southern California

2012 ◽  
Vol 102 (2) ◽  
pp. 873-877 ◽  
Author(s):  
L. E. Sumiejski ◽  
P. M. Shearer
Keyword(s):  
Southern California ◽  
Temporal Stability ◽  
Coda Q

An Improved Method for the Preparation and TEM Examination of Sharp Pointed Tips used in APFIM and STM

1990 ◽  
Vol 48 (2) ◽  
pp. 102-103
Author(s):  
E.A. Fischione ◽  
P.E. Fischione ◽  
J.J. Haugh ◽  
M.G. Burke
Keyword(s):  
Atom Probe ◽  
Preparation Process ◽  
Improved Method ◽  
Ion Milling ◽  
Polishing Process ◽  
Probe Field ◽  
Scanning Tunnelling ◽  
Stm Tips ◽  
Tunnelling Microscopy ◽  
Ion Microscopy

A common requirement for both Atom Probe Field-Ion Microscopy (APFIM) and Scanning Tunnelling Microscopy (STM) is a sharp pointed tip for use as either the specimen (APFIM) or the probe (STM). Traditionally, tips have been prepared by either chemical or electropolishing techniques. Recently, ion-milling has been successfully employed in the production of APFIM tips [1]. Conventional electropolishing techniques are applicable to a wide variety of metals, but generally require careful manual adjustments during the polishing process and may also be time-consuming. In order to reduce the time and effort involved in the preparation process, a compact, self-contained polishing unit has been developed. This system is based upon the conventional two-stage electropolishing technique in which the specimen/tip blank is first locally thinned or “necked”, and subsequently electropolished until separation occurs.[2,3] The result of this process is the production of two APFIM or STM tips. A mechanized polishing unit that provides these functions while automatically maintaining alignment has been designed and developed.

Immunoelectron microscopic localization of elastic tissue in archival material using an improved method

1990 ◽  
Vol 48 (3) ◽  
pp. 794-795
Author(s):  
J. C. Fanning ◽  
J. F. White ◽  
R. Polewski ◽  
E. G. Cleary
Keyword(s):  
Normal Animal ◽  
Animal Tissue ◽  
Elastic Tissue ◽  
Human Tissues ◽  
Improved Method ◽  
Tissue Samples ◽  
Archival Material ◽  
Immuno Electron Microscopy ◽  
Arteries And Veins ◽  
Biochemical Examination

Elastic tissue is an important component of the walls of arteries and veins, of skin, of the lungs and in lesser amounts, of many other tissues. It is responsible for the rubber-like properties of the arteries and for the normal texture of young skin. It undergoes changes in a number of important diseases such as atherosclerosis and emphysema and on exposure of skin to sunlight.We have recently described methods for the localizationof elastic tissue components in normal animal and human tissues. In the study of developing and diseased tissues it is often not possible to obtain samples which have been optimally prepared for immuno-electron microscopy. Sometimes there is also a need to examine retrospectively samples collected some years previously. We have therefore developed modifications to our published methods to allow examination of human and animal tissue samples obtained at surgery or during post mortem which have subsequently been: 1. stored frozen at -35° or -70°C for biochemical examination; 2.

The Effects of Presentation on Noise and Dental Appliances on Speech

1981 ◽  
Vol 24 (1) ◽  
pp. 151-151
Author(s):  
Lillian Glass ◽  
Sharon R. Garber ◽  
T. Michael Speidel ◽  
Gerald M. Siegel ◽  
Edward Miller
Keyword(s):  
Southern California ◽  
University Of Southern California ◽  
University Of Minnesota ◽  
School Of Medicine ◽  
Southern California School ◽  
School Of Dentistry ◽  
The University

An omission in the Table of Contents, December JSHR, has occurred. Lillian Glass, Ph.D., at the University of Southern California School of Medicine and School of Dentistry, was a co-author of the article "The Effects of Presentation on Noise and Dental Appliances on Speech" along with Sharon R. Garber, T. Michael Speidel, Gerald M. Siegel, and Edward Miller of the University of Minnesota, Minneapolis.

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