Characteristic earthquake model, 1884 -- 2011, R.I.P

Unfortunately, working scientists sometimes reflexively continue to use "buzz phrases" grounded in once prevalent paradigms that have been subsequently refuted. This can impede both earthquake research and hazard mitigation. Well-worn seismological buzz phrases include "earthquake cycle," "seismic cycle," "seismic gap," and "characteristic earthquake." They all assume that there are sequences of earthquakes that are nearly identical except for the times of their occurrence. If so, the complex process of earthquake occurrence could be reduced to a description of one "characteristic" earthquake plus the times of the others in the sequence. A common additional assumption is that characteristic earthquakes dominate the displacement on fault or plate boundary "segments." The "seismic gap" (or the effectively equivalent "seismic cycle") model depends entirely on the "characteristic" assumption, with the added assumption that characteristic earthquakes are quasi-periodic. However, since the 1990s numerous statistical tests have failed to support characteristic earthquake and seismic gap models, and the 2004 Sumatra earthquake and 2011 Tohoku earthquake both ripped through several supposed segment boundaries. Earthquake scientists should scrap ideas that have been rejected by objective testing or are too vague to be testable.Comment: 7 pages, 1 figur

Analyses of strong motion earthquake accelerograms, Volume IV - Fourier amplitude spectra; Parts V, W, and Y - Accelerograms IV294 to IV333, IIW334 to IIW336, IIW338, IIW339, IIW342 to IIW345, and IIY370 to IIY381

The corrected records analyzed in this report, Volume IV, Parts V, W, and Y, appeared in Volume II, Part V, Report No. EERL 75-52, and Volume II, Parts W and Y, Report No. EERL 75-53. Their uncorrected versions were published in Volume I, Part V, Report No. EERL 73-27; Volume I, Part W, Report No. EERL 73-28; and Volume I, Part Y, Report No. EERL 73-30

Analyses of strong motion earthquake accelerograms, Volume III - Response spectra; Part A - Accelerograms IIA001 through IIA020

This is the first volume of a series presenting earthquake response spectrum curves calculated from corrected ground accelerograms. An introduction summarizes response spectrum techniques in earthquake engineering as a background to the use of the data. For each earthquake accelerogram, two spectrum plots are given -- relative velocity response versus period on a linear scale, and a tripartite log-log plot giving relative displacement, pseudo-velocity, and pseudo-acceleration spectra. The Fourier spectrum plot is also shown on the linear plot. Digital print-outs of ordinates of the plotted curves are tabulated for each earthquake. The earthquakes in part A match the uncorrected accelerogram data of volume I and the corrected accelerogram data of volume II

Strong motion earthquake accelerograms, digitized and plotted data, Volume I - uncorrected accelerograms; Part I - Accelerograms 1I128 Through 1I140, Accelerograms from the San Fernando, California, earthquake of February 9, 1971

This issue continues the San Fernando accelerograms and contains thirteen records consisting of three each from buildings at the following addresses: 435 Oakhurst Avenue and 420 North Roxbury Drive in Beverly Hills; 1800 Century Park East and 15910 Ventura Boulevard in Los Angeles, and the record from the Borrego Springs Fire Department

Analyses of strong motion earthquake accelerograms, Volume IV - Fourier amplitude spectra; Parts Q, R and S - Accelerograms IIQ233 to IIQ243, IIR244 to IIR254, IIS255 to IIS273

The corrected records analyzed in this report, Volume IV, Parts Q, R, and S, appeared in Volume II, Parts Q and R, Report No. EERL 74-56, and Volume II, Part S, Report No. EERL 74-57. Their uncorrected versions were published in Volume I, Part Q, Report No. EERL 73-22; Volume I, Part R, Report No. EERL 73-23; and Volume I, Part S, Report No. EERL 73-24

Pre-seismic ionospheric anomalies detected before the 2016 Taiwan earthquake

On Feb. 5 2016 (UTC), an earthquake with moment magnitude 6.4 occurred in southern Taiwan, known as the 2016 (Southern) Taiwan earthquake. In this study, evidences of seismic earthquake precursors for this earthquake event are investigated. Results show that ionospheric anomalies in Total Electric Content (TEC) can be observed before the earthquake. These anomalies were obtained by processing TEC data, where such TEC data are calculated from phase delays of signals observed at densely arranged ground-based stations in Taiwan for Global Navigation Satellite Systems. This shows that such anomalies were detected within 1 hour before the event

Retrospective Evaluation of the Five-Year and Ten-Year CSEP-Italy Earthquake Forecasts

On 1 August 2009, the global Collaboratory for the Study of Earthquake Predictability (CSEP) launched a prospective and comparative earthquake predictability experiment in Italy. The goal of the CSEP-Italy experiment is to test earthquake occurrence hypotheses that have been formalized as probabilistic earthquake forecasts over temporal scales that range from days to years. In the first round of forecast submissions, members of the CSEP-Italy Working Group presented eighteen five-year and ten-year earthquake forecasts to the European CSEP Testing Center at ETH Zurich. We considered the twelve time-independent earthquake forecasts among this set and evaluated them with respect to past seismicity data from two Italian earthquake catalogs. In this article, we present the results of tests that measure the consistency of the forecasts with the past observations. Besides being an evaluation of the submitted time-independent forecasts, this exercise provided insight into a number of important issues in predictability experiments with regard to the specification of the forecasts, the performance of the tests, and the trade-off between the robustness of results and experiment duration. We conclude with suggestions for the future design of earthquake predictability experiments.Comment: 43 pages, 8 figures, 4 table

Analyses of strong motion earthquake accelerograms, Volume III - Response spectra; Part U - Accelerograms IIU294 through IIU313

This is one of a series of reports presenting earthquake response spectrum curves calculated from corrected accelerograms. In the preface to the first part, Volume III, Part A, Report No. EERL 72-80, there is a summary of response spectrum techniques in earthquake engineering which is available as background material for the data. For each earthquake accelerogram, two spectrum plots are given - relative velocity response versus period on a linear scale, and a tripartite log-log plot giving relative displacement, pseudovelocity, and pseudo-acceleration spectra. The Fourier spectrum is also shown on the linear plot. Digital printout of ordinates of the plotted curves are tabulated for each earthquake. The records analyzed in this report, Volume III, Part U, are the corrected accelerogram records contained in Volume II, Part U, Report No. EERL 75-51, and appeared in their uncorrected form in Volume I, Part U, Report No. EERL 73-26

Strong motion earthquake accelerograms, digitized and plotted data, Volume II - corrected accelerograms and integrated ground velocity and displacement curves; Parts O and P - Accelerograms IIO198 to IIO201, IIO204 to IIO208, IIO210, IIO213, IIP214 to ...

This issue, Volume II, Parts O and P, Report No. EERL 74-55, continues with the accelerograms obtained during the San Fernando earthquake of February 9, 1971, and includes three records each from the buildings at 1625 Olympic Boulevard, 4867 Sunset Boulevard, and 3345 Wilshire Boulevard in Los Angeles; two records from the building at 9841 Airport Boulevard in Los Angeles; and one record each from the Griffith Park Observatory in Los Angeles, the Utilities Building at 215 W. Broadway, and Terminal Island, both in Long Beach, the Hall of Records in San Bernardino, the Fairmont Reservoir, the University of California at Santa Barbara, the Hemet Fire Station in Hemet, the 1215 Gallery at Hoover Dam, 666 W. 19th Street in Costa Mesa, the Santa Anita Reservoir in Arcadia, the Navy Laboratory at Port Hueneme, and the Puddingstone Reservoir at San Dimas