Correction to “Regional moment: Magnitude relations for earthquakes and explosions”

Patton, Howard J.; Walter, William R.

doi:10.1029/93gl03159

Cited by 16 publications

(15 citation statements)

References 5 publications

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“…Practical problems, such as seismic hazard assessment, necessitate use of homogenized catalog. Since M W does not saturate, this is the most reliable magnitude for describing the size of an earthquake (Scordilis 2006 (Nuttli 1983;Giardini 1984;Heaton et al 1986;Patton and Walter 1993;Johnston 1996;Papazachos et al 2002;Scordilis 2006;Thingbaijam et al 2008; among many others). In this study, two methods for magnitude conversion were used; one based on Scordilis (2006) and the other using the developed correlations from the data available for the study area (as detailed below).…”

Section: Homogenization Of Earthquake Magnitudementioning

confidence: 94%

Spatial variation of seismicity parameters across India and adjoining areas

Kolathayar¹,

Sitharam²,

Vipin

2011

Nat Hazards

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An attempt has been made to quantify the variability in the seismic activity rate across the whole of India and adjoining areas (0-45°N and 60-105°E) using earthquake database compiled from various sources. Both historical and instrumental data were compiled and the complete catalog of Indian earthquakes till 2010 has been prepared. Region-specific earthquake magnitude scaling relations correlating different magnitude scales were achieved to develop a homogenous earthquake catalog for the region in unified moment magnitude scale. The dependent events (75.3%) in the raw catalog have been removed and the effect of aftershocks on the variation of b value has been quantified. The study area was divided into 2,025 grid points (1°91°) and the spatial variation of the seismicity across the region have been analyzed considering all the events within 300 km radius from each grid point. A significant decrease in seismic b value was seen when declustered catalog was used which illustrates that a larger proportion of dependent events in the earthquake catalog are related to lower magnitude events. A list of 203,448 earthquakes (including aftershocks and foreshocks) occurred in the region covering the period from 250 B.C. to 2010 A.D. with all available details is uploaded in the website

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Section: Homogenization Of Earthquake Magnitudementioning

confidence: 94%

Spatial variation of seismicity parameters across India and adjoining areas

Kolathayar¹,

Sitharam²,

Vipin

2011

Nat Hazards

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“…As the moment magnitude (M W ) scale is the most advanced and widely used magnitude scale, the original magnitudes of Indian earthquakes in different time periods have been converted to unified M W magnitudes. Several relations were proposed by different researchers to convert different magnitude scales to M W (Nuttli 1983;Giardini 1984;Kiratzi et al 1985;Heaton et al 1986;Patton and Walter 1993;Johnston 1996;Papazachos et al 1997;Scordilis 2006;Thingbaijam et al 2008;and Kolathayar et al 2011, among many others). Based on the earthquake data available from India and the adjoining area, Kolathayar et al errors and source characters such as stress drop, fault geometry, etc.…”

Section: Homogenization Of the Catalogmentioning

confidence: 98%

Characterization of Regional Seismic Source Zones in and around India

Kolathayar

Sitharam

2012

Seismological Research Letters

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“…However, the ratio of the explosion to earthquake moment also contributes to the relative Rayleigh-wave amplitude from each source. Patton and Walter (1993) perform an analysis that is similar to that of Stevens and Day (1985) that allows us to investigate the ratio of the seismic moments in equation (16). Patton and Walter (1993) investigate the relationship Stevens and McLaughlin (2001) clearly shows that the seismic moment for earthquakes are greater than those for explosions at a given m b .…”

Section: Maximum Expected Amplitudes For Rayleigh Waves From Explosionsmentioning

confidence: 99%

“…Patton and Walter (1993) perform an analysis that is similar to that of Stevens and Day (1985) that allows us to investigate the ratio of the seismic moments in equation (16). Patton and Walter (1993) investigate the relationship Stevens and McLaughlin (2001) clearly shows that the seismic moment for earthquakes are greater than those for explosions at a given m b . This implies that in general the assumption of greater Rayleigh-wave amplitudes from an earthquake relative to an explosion used in the PXD method as illustrated in Figure 3 is valid.…”

Section: Maximum Expected Amplitudes For Rayleigh Waves From Explosionsmentioning

confidence: 99%

A Probability of Detection Method for Reducing Short-Period mb-Ms False Alarm Rates

Taylor

Patton

2006

Bulletin of the Seismological Society of America

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The 20-sec m b ‫מ‬ M s discriminant is one of the most reliable and best understood methods for identifying underground nuclear explosions. To extend the discriminant to lower magnitude thresholds at regional distances it is necessary to perform the M s measurement at shorter periods. Although short-period Rayleighwave measurements have lower detection thresholds than those at 20 sec, they are more influenced by the effects of earthquake depth that cause overlap of earthquake and explosion populations. We present a technique using a probability of detection model (PXD) to estimate the probability that a surface-wave detection came from an underground explosion. The key to the method is the development of a simple analytic model to predict the maximum expected amplitude probability distribution (upper tail) from an underground explosion of a given body-wave magnitude recorded at a specified distance. The model assumes full coupling and accounts for material effects, attenuation, and amplification from tectonic release. The detection classifier is applicable when there is a signal detection above a specified signal-to-noise cutoff and the detection is of greater amplitude than the maximum expected explosion amplitude. We assume that in general, earthquakes generate larger 6-to 12-sec Rayleigh-wave amplitudes than explosions for a given body-wave magnitude. For a given sensor we define the probability of detection given that the source was an explosion. Using Bayes' Rule we determine the probability that the signal detection originated from an explosion. The surface-wave probability of detection curve for a given period and the prior probability that an explosion occurred can also be included in the formulation.We compute the conditional probability (represented as a p value) that the detected signal originated from an explosion. No assumptions regarding the non-explosion source are necessary other than the fact that the maximum amplitudes are expected to be greater than those from the explosion under full coupling conditions. Under the specified conditions, the p value will always be a small value indicating a low probability that the detected signal originated from an explosion. The p value can also be thought of as a random variable that can be combined with other discriminants in a multivariate setting. We show results of the signal detection formulation using shortperiod Rayleigh waves from earthquakes and explosions in Eurasia and compare to the traditional m b ‫מ‬ M s at different periods. For a set of earthquakes and explosions recorded at WMQ measured at a 6-to 12-sec period, false alarm rates are reduced from 28.3% for m b ‫מ‬ M s to 18.6% using the probability of detection model. Using PXD by itself as an earthquake identifier, 78% of all events are assigned a p value resulting in a false alarm rate of 22% that is better than m b ‫מ‬ M s alone for this dataset.

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Correction to “Regional moment: Magnitude relations for earthquakes and explosions”

Cited by 16 publications

References 5 publications

Spatial variation of seismicity parameters across India and adjoining areas

Spatial variation of seismicity parameters across India and adjoining areas

Characterization of Regional Seismic Source Zones in and around India

A Probability of Detection Method for Reducing Short-Period mb-Ms False Alarm Rates

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