Yield and Discrimination Studies in Stable Continental Regions

Mitchell, Brian J.

doi:10.21236/ada251590

Cited by 8 publications

(3 citation statements)

References 36 publications

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“…Q values determined from far-field intensity data should reflect Qcoda determined from the coda decay of L, waveforms since Q, , and Qcoda are similar in most regions (Mitchell 1995). Mitchell et al (1993) and Mitchell (1995) have mapped L, coda Q over most of the Earths continental regions, both active and stable. They find that Qcoda correlates well with the average crustal accretion dates of the SCRs (Australia is an exception), if allowance is made for more recent deformational episodes.…”

Section: --mentioning

confidence: 99%

Seismic moment assessment of earthquakes in stable continental regions-II. Historical seismicity

Johnston

1996

Geophysical Journal International

151

140

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S U M M A R YSeismic intensity observations contain sufficient information about the earthquake source to quantitatively constrain its scalar seismic moment, M,, and hence moment magnitude, M, within useful limits. This is valuable, especially in the pre-instrumental and early instrumental seismic eras, but also in the modern era. This study is limited to stable continental regions where intensity data are especially important for seismic hazard assessment, but the methodology is generic and can be applied to other tectonically active iegions. It builds on regression techniques developed in the Part I analysis (Johnston 1996) and applies them to isoseismal area (Ai) data. Derived regression relations for modified Mercalli isoseismal areas for levels felt to VIII yieid a predicted log(M,) or M value within specified la uncertainty bounds. Standard linear and polynomial regressions are tested against a new functional regression form proposed by Frankel ( 1994), which contains both geometrical spreading and anelastic attenuation terms. Goodness-of-fit statistics are similar, but the Frankel regression form is preferred because it is derived from physical principles of wave propagation.The Afel,-AIV regressions, with most data at epicentral distance r > 100 km, are controlled by surface-wave (L,) geometrical spreading and attenuation characteristics. For the A,,, and A,,,, regressions, r is mainly less than 100 km and body-wave propagation dominates, although near-source site and path effects are significant. The A, and A,, regressions are transitional between the L, and body-wave domains. With either the Frankel or quadratic regression, individual isoseismal areas can constrain the source event's moment magnitude within an estimated &0.30-0.45 M units except at the regression extremes. If a suite of isoseismal areas is available for the same earthquake, these uncertainties can be approximately halved by weighted averaging. This means that when good-quality isoseismal data exist for an event, they are capable of constraining its seismic moment estimate within the same order of uncertainty as individual instrumental magnitude readings. Hence, historical seismicity data may usefully be combined with instrumental data in seismic hazard analyses. A hierarchy of methods to recover an earthquake's M , or M combines the instrumental results of Part I with the isoseismal area results of this study. Finally, regressions on I, , , and number of recording stations provide the means to estimate M to within --+0.45-0.55 M units when no other data are available.

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Section: --mentioning

confidence: 99%

Seismic moment assessment of earthquakes in stable continental regions-II. Historical seismicity

Johnston

1996

Geophysical Journal International

151

140

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“…Importantly though the intensity value is VII. With the existence of the Yellow Sea Seismic Zone, the downstream Yangtze River Seismic Zone and the fact that seismic hazard is enhanced by low attenuation of seismic waves in a stable continental region [21,22] attention is required in terms of potential damage in Shanghai and its urban settlement. The nearby Liyang events are recent modern day evidence of intraplate earthquake damage.…”

Section: Intensitymentioning

confidence: 99%

Seismic hazard and risk in Shanghai and estimation of expected building damage

Cole

Burton

2008

Soil Dynamics and Earthquake Engineering

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The People's Republic of China is in the process of rapid demographic, economic and urban change including nationwide engineering and building construction at an unprecedented scale. The mega-city of Shanghai is at the centre of China's modernisation. Rapid urbanisation and building growth have increased the exposure of people and property to natural disasters. The seismic hazard of Shanghai and its vicinity is presented from a seismogenic free-zone methodology. A PGA value of 49 cm s À2 and a maximum intensity value of VII for the Chinese Seismic Intensity Scale (a scale similar to the Modified Mercalli) for a 99% probability of non-exceedance in 50 years are determined for Shanghai city. The potential building damage for three independent districts of the city centre named Putuo, Nanjing Road and Pudong are calculated using damage vulnerability matrices. It is found that old civil houses of brick and timber are the most vulnerable buildings with potentially a mean probability value of 7.4% of this building structure type exhibiting the highest damage grade at intensity VII. Crown

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“…There are numerous seismic techniques currently used to estimate the yield (Y) of a nuclear explosion, including using body waves (Nuttli, 1986(Nuttli, , 1988Patton, 1988;Vergino and Mensing, 1989;Ringdahl et al, 1992;Murphy and Barker, 2001) and scattered coda waves (Mitchell, 1991; K. R. Murphy et al, unpublished manuscript, 2007). For example, Walter et al (2007) showed that the regional P-wave source spectra for the North Korean (NK) explosion suggested an explosion of 0.5 kt at 100 m depth.…”

Section: Introductionmentioning

confidence: 99%

The Surface Wave Magnitude for the 9 October 2006 North Korean Nuclear Explosion

Bonner¹,

Herrmann²,

Harkrider³

et al. 2008

Bulletin of the Seismological Society of America

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Surface waves were generated by the North Korean nuclear explosion of 9 October 2006 and were recorded at epicentral distances up to 34°, from which we estimated a surface wave magnitude (M s ) of 2.94 with an interstation standard deviation of 0.17 magnitude units. The International Data Center estimated a body-wave magnitude (m b ) of 4.1. This is the only explosion we have analyzed that was not easily screened as an explosion based on the differences between the M s and m b estimates. Additionally, this M s predicts a yield, based on empirical M s =yield relationships, that is almost an order of magnitude larger than the 0.5-1 kt reported for this explosion. We investigate how emplacement medium effects on surface wave moment and magnitude may have contributed to the yield discrepancy.

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Yield and Discrimination Studies in Stable Continental Regions

Cited by 8 publications

References 36 publications

Seismic moment assessment of earthquakes in stable continental regions-II. Historical seismicity

Seismic moment assessment of earthquakes in stable continental regions-II. Historical seismicity

Seismic hazard and risk in Shanghai and estimation of expected building damage

The Surface Wave Magnitude for the 9 October 2006 North Korean Nuclear Explosion

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