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Advancing geodesy in the U.S. Midcontinent: workshop report Advancing geodesy in the U.S. Midcontinent: workshop report

The workshop on “Advancing Geodesy in the U.S. Midcontinent” was held from October 31 to November 1, 2012, at Northwestern University in Evanston, Illinois. The workshop included 28 participants from academia, government, and private-sector organizations that are involved in research on geodesy and earthquake hazards in the seismically active areas of the U.S. midcontinent (the region of
Authors
Michael W. Hamburger, Oliver S. Boyd, Eric Calais, Nancy E. King, Seth A. Stein

Continuing megathrust earthquake potential in Chile after the 2014 Iquique earthquake Continuing megathrust earthquake potential in Chile after the 2014 Iquique earthquake

The seismic gap theory identifies regions of elevated hazard based on a lack of recent seismicity in comparison with other portions of a fault. It has successfully explained past earthquakes (see, for example, ref. 2) and is useful for qualitatively describing where large earthquakes might occur. A large earthquake had been expected in the subduction zone adjacent to northern Chile which...
Authors
Gavin P. Hayes, Matthew W. Herman, William D. Barnhart, Kevin P. Furlong, Sebástian Riquelme, Harley M. Benz, Eric Bergman, Sergio Barrientos, Paul S. Earle, Sergey Samsonov

Grain-scale imaging and compositional characterization of cryo-preserved India NGHP 01 gas-hydrate-bearing cores Grain-scale imaging and compositional characterization of cryo-preserved India NGHP 01 gas-hydrate-bearing cores

We report on grain-scale characteristics and gas analyses of gas-hydrate-bearing samples retrieved by NGHP Expedition 01 as part of a large-scale effort to study gas hydrate occurrences off the eastern-Indian Peninsula and along the Andaman convergent margin. Using cryogenic scanning electron microscopy, X-ray spectroscopy, and gas chromatography, we investigated gas hydrate grain...
Authors
Laura A. Stern, T.D. Lorenson

Seismicity, faulting, and structure of the Koyna-Warna seismic region, Western India from local earthquake tomography and hypocenter locations Seismicity, faulting, and structure of the Koyna-Warna seismic region, Western India from local earthquake tomography and hypocenter locations

Although seismicity near Koyna Reservoir (India) has persisted for ~50 years and includes the largest induced earthquake (M 6.3) reported worldwide, the seismotectonic framework of the area is not well understood. We recorded ~1800 earthquakes from 6 January 2010 to 28 May 2010 and located a subset of 343 of the highest-quality earthquakes using the tomoDD code of Zhang and Thurber (2003...
Authors
Madan M. Dixit, Sanjay Kumar, Rufus D. Catchings, K. Suman, Dipankar Sarkar, M.K. Sen

Bayesian historical earthquake relocation: an example from the 1909 Taipei earthquake Bayesian historical earthquake relocation: an example from the 1909 Taipei earthquake

Locating earthquakes from the beginning of the modern instrumental period is complicated by the fact that there are few good-quality seismograms and what traveltimes do exist may be corrupted by both large phase-pick errors and clock errors. Here, we outline a Bayesian approach to simultaneous inference of not only the hypocentre location but also the clock errors at each station and the...
Authors
Sarah E. Minson, William H.K. Lee

Implementation of NGA-West2 ground motion models in the 2014 U.S. National Seismic Hazard Maps Implementation of NGA-West2 ground motion models in the 2014 U.S. National Seismic Hazard Maps

The U.S. National Seismic Hazard Maps (NSHMs) have been an important component of seismic design regulations in the United States for the past several decades. These maps present earthquake ground shaking intensities at specified probabilities of being exceeded over a 50-year time period. The previous version of the NSHMs was developed in 2008; during 2012 and 2013, scientists at the U.S
Authors
Sanaz Rezaeian, Mark D. Petersen, Morgan P. Moschetti, Peter Powers, Stephen C. Harmsen, Arthur D. Frankel

Path durations for use in the stochastic‐method simulation of ground motions Path durations for use in the stochastic‐method simulation of ground motions

The stochastic method of ground‐motion simulation assumes that the energy in a target spectrum is spread over a duration DT. DT is generally decomposed into the duration due to source effects (DS) and to path effects (DP). For the most commonly used source, seismological theory directly relates DS to the source corner frequency, accounting for the magnitude scaling of DT. In contrast, DP...
Authors
David M. Boore, Eric M. Thompson

Pulverization provides a mechanism for the nucleation of earthquakes at low stress on strong faults Pulverization provides a mechanism for the nucleation of earthquakes at low stress on strong faults

An earthquake occurs when rock that has been deformed under stress rebounds elastically along a fault plane (Gilbert, 1884; Reid, 1911), radiating seismic waves through the surrounding earth. Rupture along the entire fault surface does not spontaneously occur at the same time, however. Rather the rupture starts in one tiny area, the rupture nucleation zone, and spreads sequentially along...
Authors
Karen R. Felzer

Estimating earthquake magnitudes from reported intensities in the central and eastern United States Estimating earthquake magnitudes from reported intensities in the central and eastern United States

A new macroseismic intensity prediction equation is derived for the central and eastern United States and is used to estimate the magnitudes of the 1811–1812 New Madrid, Missouri, and 1886 Charleston, South Carolina, earthquakes. This work improves upon previous derivations of intensity prediction equations by including additional intensity data, correcting magnitudes in the intensity...
Authors
Oliver S. Boyd, Chris H. Cramer

Drift issues of tall buildings during the March 11, 2011 M9.0 Tohoku earthquake, Japan - Implications Drift issues of tall buildings during the March 11, 2011 M9.0 Tohoku earthquake, Japan - Implications

One of the most significant effects of the M9.0 Tohoku, Japan earthquake of March 11, 2011 is the now well-known long duration (>10 minutes) shaking of buildings in Japan – particularly those in Tokyo (~350-375 km from the epicenter) and in places as far as Osaka (~770 km from the epicenter). Although none collapsed, the strong shaking caused many tall buildings not to be functional for...
Authors
Mehmet Çelebi, Izuru Okawa

Comparison of NGA-West2 directivity models Comparison of NGA-West2 directivity models

Five directivity models have been developed based on data from the NGA-West2 database and based on numerical simulations of large strike-slip and reverse-slip earthquakes. All models avoid the use of normalized rupture dimension, enabling them to scale up to the largest earthquakes in a physically reasonable way. Four of the five models are explicitly “narrow-band” (in which the effect...
Authors
Paul A. Spudich, Badie Rowshandel, Shrey Shahi, Jack W. Baker, Brian S-J Chiou

NGA-West2 Research Project NGA-West2 Research Project

The NGA-West2 project is a large multidisciplinary, multi-year research program on the Next Generation Attenuation (NGA) models for shallow crustal earthquakes in active tectonic regions. The research project has been coordinated by the Pacific Earthquake Engineering Research Center (PEER), with extensive technical interactions among many individuals and organizations. NGA-West2...
Authors
Yousef Bozorgnia, Norman A. Abrahamson, Linda Al Atik, Timothy D. Ancheta, Gail M. Atkinson, Jack W. Baker, Annemarie S. Baltay Sundstrom, David M. Boore, Kenneth W. Campbell, Brian S.J. Chiou, Robert B. Darragh, Steve Day, Jennifer Donahue, Robert W. Graves, Nick Gregor, Thomas C. Hanks, I. M. Idriss, Ronnie Kamai, Tadahiro Kishida, Albert Kottke, Stephen A. Mahin, Sanaz Rezaeian, Badie Rowshandel, Emel Seyhan, Shrey Shahi, Tom Shantz, Walter Silva, Paul A. Spudich, Jonathan P. Stewart, Jennie Watson-Lamprey, Kathryn Wooddell, Robert Youngs
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