scholarly journals TriNet “ShakeMaps”: Rapid Generation of Peak Ground Motion and Intensity Maps for Earthquakes in Southern California

1999 ◽  
Vol 15 (3) ◽  
pp. 537-555 ◽  
Author(s):  
David J. Wald ◽  
Vincent Quitoriano ◽  
Thomas H. Heaton ◽  
Hiroo Kanamori ◽  
Craig W. Scrivner ◽  
...  
Keyword(s):  
Ground Motion ◽  
Emergency Response ◽  
Spatial Interpolation ◽  
Southern California ◽  
Ground Motions ◽  
Peak Ground Motion ◽  
The World ◽  
Motion Parameters ◽  
Dependent Site ◽  
Rapid Generation

Rapid (3-5 minutes) generation of maps of instrumental ground-motion and shaking intensity is accomplished through advances in real-time seismographic data acquisition combined with newly developed relationships between recorded ground-motion parameters and expected shaking intensity values. Estimation of shaking over the entire regional extent of southern California is obtained by the spatial interpolation of the measured ground motions with geologically based frequency and amplitude-dependent site corrections. Production of the maps is automatic, triggered by any significant earthquake in southern California. Maps are now made available within several minutes of the earthquake for public and scientific consumption via the World Wide Web; they will be made available with dedicated communications for emergency response agencies and critical users.

Event Detection Performance of the PLUM Earthquake Early Warning Algorithm in Southern California

2019 ◽  
Vol 109 (4) ◽  
pp. 1524-1541 ◽  
Author(s):  
Elizabeth S. Cochran ◽  
Julian Bunn ◽  
Sarah E. Minson ◽  
Annemarie S. Baltay ◽  
Deborah L. Kilb ◽  
...  
Keyword(s):  
Los Angeles ◽  
Ground Motion ◽  
Early Warning ◽  
Southern California ◽  
Ground Motions ◽  
Tohoku Earthquake ◽  
Prediction Equation ◽  
Earthquake Early Warning ◽  
Japan Meteorological Agency ◽  
Origin Time

Abstract We test the Japanese ground‐motion‐based earthquake early warning (EEW) algorithm, propagation of local undamped motion (PLUM), in southern California with application to the U.S. ShakeAlert system. In late 2018, ShakeAlert began limited public alerting in Los Angeles to areas of expected modified Mercalli intensity (IMMI) 4.0+ for magnitude 5.0+ earthquakes. Most EEW systems, including ShakeAlert, use source‐based methods: they estimate the location, magnitude, and origin time of an earthquake from P waves and use a ground‐motion prediction equation to identify regions of expected strong shaking. The PLUM algorithm uses observed ground motions directly to define alert areas and was developed to address deficiencies in the Japan Meteorological Agency source‐based EEW system during the 2011 Mw 9.0 Tohoku earthquake sequence. We assess PLUM using (a) a dataset of 193 magnitude 3.5+ earthquakes that occurred in southern California between 2012 and 2017 and (b) the ShakeAlert testing and certification suite of 49 earthquakes and other seismic signals. The latter suite includes events that challenge the current ShakeAlert algorithms. We provide a first‐order performance assessment using event‐based metrics similar to those used by ShakeAlert. We find that PLUM can be configured to successfully issue alerts using IMMI trigger thresholds that are lower than those implemented in Japan. Using two stations, a trigger threshold of IMMI 4.0 for the first station and a threshold of IMMI 2.5 for the second station PLUM successfully detect 12 of 13 magnitude 5.0+ earthquakes and issue no false alerts. PLUM alert latencies were similar to and in some cases faster than source‐based algorithms, reducing area that receives no warning near the source that generally have the highest ground motions. PLUM is a simple, independent seismic method that may complement existing source‐based algorithms in EEW systems, including the ShakeAlert system, even when alerting to light (IMMI 4.0) or higher ground‐motion levels.

Dynamic characteristics of ground motions due to blasting

1979 ◽  
Vol 69 (2) ◽  
pp. 627-639
Author(s):  
Kenneth Medearis
Keyword(s):  
Ground Motion ◽  
Dynamic Characteristics ◽  
Research Effort ◽  
Ground Motions ◽  
Response Spectra ◽  
Dominant Frequency ◽  
Peak Ground Velocity ◽  
Peak Ground Motion ◽  
Computer Analyses ◽  
Damage Criteria

abstract There is considerable evidence that more rational damage criteria need to be generated with regard to low-rise structures subjected to seismic ground motions. There is not sufficient basis for specifying a maximum ground particle velocity criterion, such as 2 in/sec. A peak ground velocity guideline does not currently take into account a number of important parameters, including the predominant frequencies of the ground motion excitation and the structure being excited. Although a number of states have adopted peak-velocity criteria, such criteria have been ruled inadequate in certain legal decisions affecting blasting operations. The development of more rational damage criteria is thus of significant importance. Such criteria must necessarily consider the dynamic characteristics of seismic ground motions, i.e., pertinent and dominant frequency characteristics, response and Fourier spectra, etc. Very little analysis has been done with regard to determining the dynamic characteristics of blasting ground motions, however. This paper describes a research effort concerned with the determination of these characteristics for a sizeable number of actual blasting records using appropriate theoretical and computer analyses. Peak ground motion versus charge and distance relationships were derived, as well as pertinent response spectra. Statistical representations of the latter were also obtained using some 200 ground motions.

Istanbul at the Threshold: An Evaluation of the Seismic Risk in Istanbul

2007 ◽  
Vol 23 (1) ◽  
pp. 63-75 ◽  
Author(s):  
Jacob H. Pyper Griffiths ◽  
Ayhan Irfanoglu ◽  
Santiago Pujol
Keyword(s):  
Ground Motion ◽  
Emergency Response ◽  
Seismic Risk ◽  
Ground Motions ◽  
Convincing Evidence ◽  
Severe Damage ◽  
Future Earthquake ◽  
The City ◽  
Better Than

There is no convincing evidence indicating that future ground motion in at least two-thirds of Istanbul, Turkey, shall be less demanding than the ground motions that devastated the city of Düzce, Turkey, in 1999. Comparison of vulnerability indices calibrated for Turkish construction indicates that the structures of the buildings in Istanbul are no better than the structures of buildings in Düzce. On the basis of these arguments, we project that a future earthquake near Istanbul may cause severe damage or collapse approximately quarter of a million buildings. Leaving the vulnerable buildings as they are and organizing for emergency response is not an option for Istanbul.

Identification Methods of Important Parameters for Near-Fault Pulse-Type Ground Motions

2012 ◽  
Vol 594-597 ◽  
pp. 1688-1691
Author(s):  
Ming Li ◽  
Qiao Jin ◽  
Yong Liu ◽  
He Yuan ◽  
Zhe Zhe Sun
Keyword(s):  
Ground Motion ◽  
Peak Velocity ◽  
Ground Motions ◽  
Velocity Pulse ◽  
Identification Methods ◽  
Near Fault ◽  
Pulse Type ◽  
Pulse Peak ◽  
Motion Parameters ◽  
Near Fault Ground Motion

during the process of fitting or synthesizing near-fault ground motion，parameters of the equivalent velocity pulse need to be decided based on seismic records．Thus, it is a key problem that how to identify these parameters from the records．Pulse period and pulse peak velocity are important parameters in the equivalent velocity pulse models．In this study，various methods on identifying these parameters are reviewed．It is shown that all the existing methods have limitations，especially for the irregular seismic records．Finally，problems need to be further studied is pointed out.

scholarly journals Preliminary work on an early warning and rapid response program for moderate earthquakes

1995 ◽  
Vol 85 (4) ◽  
pp. 1257-1265
Author(s):  
Craig W. Scrivner ◽  
Donald V. Helmberger
Keyword(s):  
Ground Motion ◽  
Southern California ◽  
San Andreas Fault ◽  
Ground Motions ◽  
Source Parameters ◽  
Reverse Direction ◽  
Peak Displacement ◽  
San Andreas ◽  
Single Station ◽  
Sierra Madre

Abstract Warning of imminent ground shaking due to a large earthquake would be useful to a variety of agencies. This kind of ground-motion prediction is possible in southern California for events with magnitude less than 6, where path effects dominate. The 28 June 1991 Sierra Madre earthquake is presented as a test case for this concept. A single-station inversion of the record from the Pasadena station 20 km SW of the epicenter produces reasonable source parameters for the event. With these source parameters and a library of Green's functions calculated for an average southern California crustal model, ground motions can be predicted throughout the region. In particular, since the peak displacement for the Sierra Madre event occurs at Pasadena before ground motion begins at a station near the San Andreas Fault in San Bernardino, ground motions near the San Andreas Fault can be calculated before the seismic energy has propagated into the area. Considering this scenario in the reverse direction, records from a station near an earthquake on the San Andreas Fault could be used to predict ground motions in the metropolitan Los Angeles area. Broadband, high-dynamic-range seismic instruments produce high-quality records for events over a wide magnitude range. Thus, the development of a warning system can be approached in stages, starting with small events. With path effects determined by modeling moderate-size events, work can begin on developing distributed fault models to predict ground motions of great earthquakes.

Losses to Single-Family Housing from Ground Motions in the 1994 Northridge, California, Earthquake

2004 ◽  
Vol 20 (3) ◽  
pp. 1021-1045 ◽  
Author(s):  
Robert L. Wesson ◽  
David M. Perkins ◽  
Edgar V. Leyendecker ◽  
Richard J. Roth ◽  
Mark D. Petersen
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Earthquake Ground Motion ◽  
Single Family ◽  
Building Stock ◽  
Ground Motion Parameters ◽  
Family Housing ◽  
Motion Parameters ◽  
Insured Losses ◽  
Aggregate Loss

The distributions of insured losses to single-family housing following the 1994 Northridge, California, earthquake for 234 ZIP codes can be satisfactorily modeled with gamma distributions. Regressions of the parameters in the gamma distribution on estimates of ground motion, derived from ShakeMap estimates or from interpolated observations, provide a basis for developing curves of conditional probability of loss given a ground motion. Comparison of the resulting estimates of aggregate loss with the actual aggregate loss gives satisfactory agreement for several different ground-motion parameters. Estimates of loss based on a deterministic spatial model of the earthquake ground motion, using standard attenuation relationships and NEHRP soil factors, give satisfactory results for some ground-motion parameters if the input ground motions are increased about one and one-half standard deviations above the median, reflecting the fact that the ground motions for the Northridge earthquake tended to be higher than the median ground motion for other earthquakes with similar magnitude. The results give promise for making estimates of insured losses to a similar building stock under future earthquake loading.

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