Publications
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Tidal calibration of Plate Boundary Observatory borehole strainmeters: Roles of vertical and shear coupling
A multicomponent borehole strainmeter directly measures changes in the diameter of its cylindrical housing at several azimuths. To transform these measurements to formation strains requires a calibration matrix, which must be estimated by analyzing the installed strainmeter's response to known strains. Typically, theoretical calculations of Earth tidal strains serve as the known strains. This pape
Authors
Evelyn Roeloffs
Implementation of the Next Generation Attenuation (NGA) ground-motion prediction equations in Fortran and R
This report presents two methods for implementing the earthquake ground-motion prediction equations released in 2008 as part of the Next Generation Attenuation of Ground Motions (NGA-West, or NGA) project coordinated by the Pacific Earthquake Engineering Research Center (PEER). These models were developed for predicting ground-motion parameters for shallow crustal earthquakes in active tectonic re
Authors
James Kaklamanos, David M. Boore, Eric M. Thompson, Kenneth W. Campbell
Orientation-independent, nongeometric-mean measures of seismic intensity from two horizontal components of motion
New measures of spectral intensity based on the horizontal components of ground shaking are introduced. These new measures are independent of the in situ orientation of the recordings and encompass the full range of spectral amplitudes over all possible rotation angles. Unlike previously introduced measures that are also orientation independent, no geometric means are used in the computation of th
Authors
David M. Boore
Introduction to special section on phenomenology, underlying processes, and hazard implications of aseismic slip and nonvolcanic tremor
This paper introduces the special section on the "phenomenology, underlying processes, and hazard implications of aseismic slip and nonvolcanic tremor" by highlighting key results of the studies published in it. Many of the results indicate that seismic and aseismic manifestations of slow slip reflect transient shear displacements on the plate interface, with the outstanding exception of northern
Authors
Joan Gomberg
Fault zone structure from topography: signatures of en echelon fault slip at Mustang Ridge on the San Andreas Fault, Monterey County, California
We used high-resolution topography to quantify the spatial distribution of scarps, linear valleys, topographic sinks, and oversteepened stream channels formed along an extensional step over on the San Andreas Fault (SAF) at Mustang Ridge, California. This location provides detail of both creeping fault landform development and complex fault zone kinematics. Here, the SAF creeps 10–14 mm/yr slower
Authors
Stephen B. DeLong, George E. Hilley, Michael J. Rymer, Carol Prentice
Infrasonic harmonic tremor and degassing bursts from Halema'uma'u Crater, Kilauea Volcano, Hawaii
The formation, evolution, collapse, and subsequent resurrection of a vent within Halema'uma'u Crater, Kilauea Volcano, produced energetic and varied degassing signals recorded by a nearby infrasound array between 2008 and early 2009. After 25 years of quiescence, a vent-clearing explosive burst on 19 March 2008 produced a clear, complex acoustic signal. Near-continuous harmonic infrasonic tremor f
Authors
David Fee, Milton Garcés, Matt Patrick, Bernard Chouet, Phil Dawson, Donald A. Swanson
Aftershocks are well aligned with the background stress field, contradicting the hypothesis of highly-heterogeneous crustal stress
It has been proposed that the crustal stress field contains small-length-scale heterogeneity of much larger amplitude than the uniform background stress. This model predicts that earthquake focal mechanisms should reflect the loading stress rather than the uniform background stress. So, if the heterogeneous stress hypothesis is correct, focal mechanisms before and after a large earthquake should a
Authors
Jeanne L. Hardebeck
Inelastic off-fault response and three-dimensional dynamics of earthquake rupture on a strike-slip fault
Large dynamic stress off the fault incurs an inelastic response and energy loss, which contributes to the fracture energy, limiting the rupture and slip velocity. Using an explicit finite element method, we model three-dimensional dynamic ruptures on a vertical strike-slip fault in a homogeneous half-space. The material is subjected to a pressure-dependent Drucker-Prager yield criterion. Initial s
Authors
D. J. Andrews, Shuo Ma
Method for calculating self-noise spectra and operating ranges for seismographic inertial sensors and recorders
Understanding the performance of sensors and recorders is prerequisite to making appropriate use of them in seismology and earthquake engineering. This paper explores a critical aspect of instrument performance, the “self” noise level of the device and the amplitude range it can usefully record. Self noise limits the smallest signals, while instrument clipping level creates the upper limit (above
Authors
John R. Evans, F. Followill, Charles R. Hutt, R.P. Kromer, R.L. Nigbor, A. T. Ringler, J.M. Steim, E. Wielandt
Reply to “Comment on ‘Near-surface location, geometry, and velocities of the Santa Monica fault zone, Los Angeles, California’ by R. D. Catchings, G. Gandhok, M. R. Goldman, D. Okaya, M. J. Rymer, and G. W. Bawden” by T. L. Pratt and J. F. Dolan
In a comment on our 2008 paper (Catchings, Gandhok, et al., 2008) on the Santa Monica fault in Los Angeles, California, Pratt and Dolan (2010) (herein referred to as P&D) cite numerous objections to our work, inferring that our study is flawed. However, as shown in our reply, their objections contradict their own published works, published works of others, and proven seismic methodologies. Rather
Authors
Rufus D. Catchings, Michael J. Rymer, Mark R. Goldman, Gerald W. Bawden
The ShakeOut earthquake scenario: Verification of three simulation sets
This paper presents a verification of three simulations of the ShakeOut scenario, an Mw 7.8 earthquake on a portion of the San Andreas fault in southern California, conducted by three different groups at the Southern California Earthquake Center using the SCEC Community Velocity Model for this region. We conducted two simulations using the finite difference method, and one by the finite element me
Authors
J. Bielak, R.W. Graves, K.B. Olsen, R. Taborda, L. Ramirez-Guzman, S.M. Day, G.P. Ely, D. Roten, T.H. Jordan, P.J. Maechling, J. Urbanic, Y. Cui, G. Juve
The water table
The water table is a fundamental concept in hydrogeology, yet it is frequently incorrectly defined. For example, both the NGWA (2003) and AGI (Neuendorf et al. 2005) glossaries define the water table as the atmospheric pressure surface that is coincident with the top of the zone of saturation. This definition is also found occasionally in groundwater textbooks as well as in primers, where it is si
Authors
Thomas L. Holzer