Macroseismic field of the March 4, 1977 Vrancea earthquake

Radu, C.; Polonic, Gabriela; Apopei, I.

doi:10.1016/0040-1951(79)90062-3

Cited by 13 publications

(14 citation statements)

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“…In this case, all necessary parameters of the model have been determined using the database, which does not include the records from these events. The intensity was evaluated from the earthquake records and compared with reported data-maps of seismic intensity distribution (Radu and Polonic 1979, Radu et al 1987, Radu and Utale 1990. Table 5 lists the results of the comparison.…”

Section: The Vrancea (Romania) Regionmentioning

confidence: 99%

Seismic Intensity and Fourier Acceleration Spectra: Revised Relationship

Sokolov

2002

Earthquake Spectra

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This paper presents a revised method for estimating the seismic intensity (MMI or MSK scale) using Fourier amplitude spectra (FAS) of ground acceleration. The improvement of the recently proposed technique (Sokolov and Chernov 1998) has been made on the basis of the data, which were obtained recently during strong earthquakes that occurred throughout the world. The total amount of the used data (horizontal components of ground-motion recordings) is about 1,150 records, while the database of 300 recordings was used in the previous study. The method implies that the seismic intensity is determined by the level of ground motion spectral amplitudes in the frequency range of 0.4–13 Hz. The corresponding empirical relationships between FAS and each intensity level were developed. The method is validated by comparison of the results of the technique application with the empirical data, which have not been included in the database. The Romanian earthquakes (intermediate-depth events of 1977, 1986, and 1990) and the recent 1999 Hector Mine earthquake in southern California were used for this purpose. In general, the FAS intensity shows a good agreement with the reported intensity, and the average residuals do not exceed ±0.3 intensity units and standard deviation is about 0.4-0.6. Evaluation of seismic intensity distribution using region- and site-dependent spectral models, as well as calculation of instrumental intensity map for the recent 1999 Chi-Chi earthquake, Taiwan, show that the FAS intensity clearly reflects the regional (source scaling and attenuation relation) and local (soil response) peculiarities of ground motion.

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Section: The Vrancea (Romania) Regionmentioning

confidence: 99%

Seismic Intensity and Fourier Acceleration Spectra: Revised Relationship

Sokolov

2002

Earthquake Spectra

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“…For each square element, the average intensity value has been evaluated from the direct macroseismic observations, by transforming the irregular macroseismic data distribution into an ordered set of values that can be processed. The primary intensity observations have been taken from maps published by Radu et al (1979) and Grigorova et al (1978).…”

Section: Methodsmentioning

confidence: 99%

Studies on the contribution of some geological factors to seismic hazard

Spânoche¹

1990

Nat Hazards

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The present study is primarily meant to make a separation of the amplification effects in the intensity distribution within the macroseismic field function of their different causes, i.e. the activation of some regional tectonic lines during the seismic motion and local seismogeological conditions.With this end in view, the methodology used consists of filtering the direct macroseismic observations by means of the weighted mean-values method and outlining the regional and local field anomalies.The regional anomaly map of the macroseismic field of the 4 March 1977 Vrancea earthquake, including the southern and south-eastern part of the Outer Carpathian Zone, has been analyzed. Some dislocations, located in the platform basement, which functioned as seismic energy amplifiers during the event, have been identified.The results obtained can be used in seismotectonic and microzoning studies.

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“…Consequently, these results should be combined with expert opinion to ascertain more reliable rankings that consider construction type and its likely response to strong ground shaking. For example, the apparent low vulnerability of Romania is largely driven by the high intensities assigned in post-disaster surveys from the 1977 M W 7.5 Vrancea earthquake (e.g., Radu et al 1979). These intensities have been incorporated into the Atlas of ShakeMaps in an effort to replicate observed shaking for this event (see http://earthquake.usgs.gov/eqcenter/shakemap/atlas/shake/197703041921/).…”

Section: Ranking Of Country Earthquake Vulnerabilitymentioning

confidence: 99%

An Atlas of ShakeMaps and population exposure catalog for earthquake loss modeling

Allen

Wald

Earle

et al. 2009

Bull Earthquake Eng

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We present an Atlas of ShakeMaps and a catalog of human population exposures to moderate-to-strong ground shaking (EXPO-CAT) for recent historical earthquakes . The common purpose of the Atlas and exposure catalog is to calibrate earthquake loss models to be used in the US Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER). The full ShakeMap Atlas currently comprises over 5,600 earthquakes from January 1973 through December 2007, with almost 500 of these maps constrained-to varying degrees-by instrumental ground motions, macroseismic intensity data, community internet intensity observations, and published earthquake rupture models. The catalog of human exposures is derived using current PAGER methodologies. Exposure to discrete levels of shaking intensity is obtained by correlating Atlas ShakeMaps with a global population database. Combining this population exposure dataset with historical earthquake loss data, such as PAGER-CAT, provides a useful resource for calibrating loss methodologies against a systematically-derived set of ShakeMap hazard outputs. We illustrate two example uses for EXPO-CAT; (1) simple objective ranking of country vulnerability to earthquakes, and; (2) the influence of time-of-day on earthquake mortality. In general, we observe that countries in similar geographic regions with similar construction practices tend to cluster spatially in terms of relative vulnerability. We also find little quantitative evidence to suggest that time-of-day is a significant factor in earthquake mortality. Moreover, earthquake mortality appears to be more systematically linked to the population exposed to severe ground shaking (Modified Mercalli Intensity VIII+). Finally, equipped with the full Atlas of ShakeMaps, we merge each of these maps and find the maximum estimated peak ground acceleration at any grid point in the world for the past 35 years. We subsequently compare this "composite T. I. Allen and M. G. Hearne-contracted through Synergetics Incorporated.123 702 Bull Earthquake Eng (2009) 7:701-718 ShakeMap" with existing global hazard models, calculating the spatial area of the existing hazard maps exceeded by the combined ShakeMap ground motions. In general, these analyses suggest that existing global, and regional, hazard maps tend to overestimate hazard. Both the Atlas of ShakeMaps and EXPO-CAT have many potential uses for examining earthquake risk and epidemiology. All of the datasets discussed herein are available for download on the PAGER Web page

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Macroseismic field of the March 4, 1977 Vrancea earthquake

Cited by 13 publications

References 0 publications

Seismic Intensity and Fourier Acceleration Spectra: Revised Relationship

Seismic Intensity and Fourier Acceleration Spectra: Revised Relationship

Studies on the contribution of some geological factors to seismic hazard

An Atlas of ShakeMaps and population exposure catalog for earthquake loss modeling

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