21 results on '"Earthquake catalog"'
Search Results
2. A Comprehensive Earthquake Catalog for Iraq in Terms of Moment Magnitude
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Najah Abd, Nazar M. S. Numan, Wathiq Abdulnaby, Tuna Onur, Hanan Mahdi, Rengin Gök, Haydar Al-Shukri, Hussein K. Chlaib, Ammar M. Shakir, and Taher H. Ameen
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010504 meteorology & atmospheric sciences ,Magnitude (mathematics) ,Moment tensor ,Moment magnitude scale ,010502 geochemistry & geophysics ,01 natural sciences ,Coda ,Earthquake catalog ,Moment (mathematics) ,Geophysics ,Geological survey ,Seismology ,Geology ,0105 earth and related environmental sciences - Abstract
A comprehensive earthquake catalog was compiled for Iraq and neighboring areas as part of a broader probabilistic seismic‐hazard assessment project. The Iraq Seismic Network (ISN) was established in 1976 and became operational in the early 1980s. However, recording and reporting of seismic data has been intermittent in Iraq. Hence, events were collected from various sources, including the ISN when available, International Seismological Centre (ISC), European‐Mediterranean Seismological Centre, U.S. Geological Survey Centennial Catalog, Global Centroid Moment Tensor solutions, and Ambraseys’ extensive work on cataloging of instrumental era earthquakes in the Middle East (e.g., Ambraseys, 1978, 2001, 2009). We supplement these with new direct moment magnitude calculations based on coda calibration technique. For many of the larger events in the catalog, more than one magnitude is available. Directly calculated moment magnitudes ( M w) were favored, followed by body‐wave magnitude ( m b) obtained from the ISC. Where no directly calculated M w was available, other magnitude scales were converted to M w using relationships compatible with the local catalog. The resulting earthquake catalog spans from the year 1900 until the end of 2009, covers the region bounded by 26°–40° N latitudes and 36°–51° E longitudes, and includes more than 18,000 earthquakes, of which roughly 4000 are M w 4.0 or larger. more...
- Published
- 2017
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Catalog
3. 2012 Seismicity Quiescence in Taiwan a Result of Site‐Effect Artifacts
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Yih-Min Wu, Tz-Shin Lai, and Himanshu Mittal
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Earthquake catalog ,Geophysics ,010504 meteorology & atmospheric sciences ,Magnitude (mathematics) ,Central weather bureau ,Induced seismicity ,010502 geochemistry & geophysics ,01 natural sciences ,Seismology ,Geology ,Standard deviation ,0105 earth and related environmental sciences - Abstract
A significant seismic quiescence in Taiwan was reported by Wu and Chiao (2006) before the occurrence of the 1999 M w 7.6 Chi‐Chi earthquake. A similar kind of activity was also observed in the 2012 earthquake catalog reported by Central Weather Bureau (CWB). Seven months in the 2012 catalog seem to have lower monthly seismicity rates than the one standard deviation below the mean (673±82) for earthquakes with M L ≥2.0. Here, we checked the seismic network in Taiwan and found that some new seismic stations, including the Broadband Array in Taiwan for Seismology (BATS), were incorporated within the Taiwan Central Weather Bureau Seismic Network (CWBSN) since 2012. Most of these BATS stations are located on hard‐rock sites, which may affect magnitude estimation because of their site characteristics. To account for the impact of site effect, earthquake catalog data during the period of 1994 to 2014 was collected and station correction was calculated for each station. A strong correlation is found between station corrections determined in this study and geological settings of the region. Stations located on soil sites have high amplifications with negative station corrections. On the other hand, stations located on hard‐rock sites have low amplifications with positive station corrections. After applying station correction, the mean seismicity rate is found to be 716 events per month with a standard deviation of 76 events for earthquakes with M L ≥2.0. We conclude that the reason behind the apparent low seismicity in 2012 is due to the installation of new seismic stations on rock sites, which lead to underestimation of M L . more...
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- 2016
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4. The Algerian Homogenized Macroseismic Database (267–1989): A Deeper Insight into the Algerian Historical Seismicity
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Manel Benmedjber, Seid Bourouis, Said Maouche, Farida Ousadou, Amal Sebaï, Ahmed Grigahcene, Yasmina Rouchiche, Assia Harbi, Djamel Aïni, and A. Ayadi
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Maximum intensity ,Earthquake catalog ,Geophysics ,Database ,Homogeneous ,Induced seismicity ,computer.software_genre ,computer ,Geology ,Seismology - Abstract
Online Material: Sources of information on earthquakes and earthquake list. Studying the effects of past earthquakes is an important component of predicting the effects of future earthquakes, and knowledge of historic earthquakes is important for understanding future earthquakes. The revision of the historical seismicity of Algeria started at the beginning of this century and is still going on (e.g., Harbi, Benouar, and Benhallou, 2003; Sebai and Bernard, 2008). The final objective of this reappraisal is to produce an earthquake catalog for Algeria that is as homogeneous as possible, compiled in a unique format, and covering a period of time going back as far as the existing data allow. The idea to make the macroseismic database accessible to the scientific community arose after the compilation and publication of the earthquake catalog of eastern Algeria (Harbi et al. , 2010), which became a starting point for a catalog dealing with the whole country. One of our objectives, when we performed that work, was to check the validity of the parameters reported in the earthquake catalog that we compiled from previous works, particularly for the damaging and destructive earthquakes. The only way to achieve this goal was to reexamine all the available seismological compilations (see the Materials for the Investigation of Algeria Seismicity section). We noticed that some authors (e.g., Roussel, 1973; Mezcua and Martinez, 1983) assigned an intensity value to the earthquakes without quoting their sources. This implies some uncertainty, particularly when the intensity is higher than VI, and suggests a damaging earthquake. Two important reasons led us to revise the macroseismic parameters of Algerian earthquakes, particularly the maximum intensity values, and to assess or reassess the intensities in terms of one single intensity scale, the European … more...
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- 2015
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5. The Wood–Anderson of Trieste (Northeast Italy): One of the Last Operating Torsion Seismometers
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Stefania Gentili, Angela Saraò, Denis Sandron, Giovanni Francesco Gentile, M. Santulin, Dario Slejko, and A. Rebez
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Seismometer ,Earthquake catalog ,Engineering ,Geophysics ,business.industry ,business ,Seismogram ,Seismology - Abstract
Online Material: Earthquake catalog. The Wood–Anderson (WA) torsion seismograph, used by Richter (1935) for the definition of the local magnitude ( M L) of an earthquake, has been abandoned over time due to the cumbersome nature of its use. With the progress of technology, modern digital broadband (BB) instruments have replaced older instruments such as the WA, and the equivalent M L, obtained from simulated WA seismograms after convolution of the recorded BB data with a proper transfer function (Bormann, 2002a,b), has replaced the WA M L. Despite the paucity of WA instruments today, the M L in its original form remains relevant for continuity with old earthquake catalogs and as a long-standing reference for all other magnitude scales up to approximately M L 6.5. For larger earthquakes, the M L scale progressively underestimates the actual energy release and M L is said to saturate (Kanamori, 1983). Even so, M L is a good predictor of structural damage caused by earthquakes because many buildings have resonant periods close to that of the WA seismograph (0.8 s). In Trieste, located in northeastern Italy, there is one of the few stations equipped with an original pair of WA instruments that are still operating. The two horizontal WA seismometers (Lehner-Griffith TS-220) were installed in September 1971 and have been managed since then by the Osservatorio Geofisico Sperimentale, presently the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS). The Trieste station was part of the Worldwide Standardized Seismographic Station Network (WWSSN) with the code TRI-117, and it dates its operation back to 29 July 1963. At that time, three Benioff seismometers were employed as short-period seismographs, and three Ewing-Press seismometers … more...
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- 2015
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6. Solving the Mystery: The 21 October 1880 Portuguese Earthquake
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José R. Ribeiro, Ana Isabel Ribeiro, and Ana P. Correia
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geography ,geography.geographical_feature_category ,History ,Magnitude (mathematics) ,Induced seismicity ,Archaeology ,language.human_language ,Newspaper ,Earthquake catalog ,Geophysics ,Peninsula ,Epicenter ,language ,Portuguese ,Seismology ,Systematic search - Abstract
Online Material: Relevant accounts for intensity estimates of the 21 October 1880 Portuguese earthquake. Despite recent important contributions to the completeness of earthquake catalogs, there are still significant gaps in our knowledge about the preinstrumental seismicity of the Iberian Peninsula. This is true even for the second half of the nineteenth century, in spite of the vast increase in the number of scientific institutions and newspapers in these decades. In the last extensive revision of the Iberian earthquake catalog (Rodriguez de la Torre, 1990a,b), the number of known earthquakes occurring between 1851 and 1900 increased from 620 to 2066 as a result of the systematic search conducted by Rodriguez de la Torre mainly using Spanish sources. Relative to earlier earthquake catalogs, the new data enabled (Martinez Solares and Mezcua, 2002; Mezcua et al. , 2004) to present a very much improved catalog of the earthquakes that occurred in the Iberian Peninsula and its vicinity, with a new assessment of epicenters and magnitudes of the major events, through application of the Bakun and Wentworth (BW Bakun et al. , 2003). As Martinez Solares and Mezcua (2002) and Mezcua et al. (2004) pointed out, the B&W procedure was only applied to events for which there were enough intensity values. Although registered in this catalog, one major Iberian earthquake that is still waiting for epicenter and magnitude determinations is the 21 October 1880 (6:41 a.m.) earthquake. The event was unknown until 1990, when it was discovered by Fernando Rodriguez de la Torre (1990a) in Spanish and Portuguese nineteenth century newspapers. With this new information revealed, the 1880 earthquake was included in the catalog of Martinez … more...
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- 2015
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7. ISMD, a Web Portal for Real-Time Processing and Dissemination of INGV Strong-Motion Data
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Giulio Selvaggi, Paolo Augliera, Alberto Michelini, Salvatore Mazza, Ezio D'Alema, Sara Lovati, Marco Cattaneo, Gianlorenzo Franceschina, Marco Massa, Alessandro Amato, and Simone Marzorati
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Earthquake catalog ,Engineering ,Geophysics ,business.industry ,Seismic risk ,Telecommunications ,business ,Data archive ,Continuous data - Abstract
Online Material: Earthquake catalog and strong motion stations. In Italy, strong‐motion monitoring started in the early 1970s, when the Rete Accelerometrica Nazionale (RAN, the Italian National Strong Motion Network; http://www.protezionecivile.gov.it/jcms/it/ran.wp; see Data and Resources for a complete listing of all websites listed in this article) was designed and installed by the Agenzia Nazionale per le Nuove Tecnologie, l’Energia e lo Sviluppo Economico Sostenibile (ENEA) and ENEL (an Italian power company). The aim was to evaluate the seismic risk in connection with the construction of nuclear power plants. Since 1997, the RAN (Gorini et al. , 2010) has been run by the Dipartimento della Protezione Civile (DPC). At present, the RAN includes about 500 digital strong‐motion stations. The contribution of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) to Italian strong‐motion monitoring started some years later. Through the 2004–2006 agreement between the INGV and the DPC (Strong‐Motion Stations Project), the INGV began the phase of strong‐motion monitoring (Augliera et al. , 2010, 2011). Since 2006, a complete renewal of the (velocimetric) Rete Sismica Nazionale (RSN; Amato and Mele, 2008) was made by installing accelerometers to sites where broadband RSN velocimeters were already present. Altogether, the current ∼150 high‐dynamics digital strong‐motion stations that cover the Italian territory constitute the INGV strong‐motion network. The first channel chosen by the INGV to disseminate the recorded waveforms was through the European Integrated Data Archive (EIDA; http://eida.rm.ingv.it/; http://www.orfeus-eu.org/eida/eida.html), a web portal devoted to seismic data exchange that was developed in the framework of the Network of Research Infrastructures for European Seismology (NERIES) European project (www.neries-eu.org, Networking Activity 3 [NA3]). Since 2008, the INGV raw signals have been downloadable in the Standard for the Exchange of Earthquake Data (SEED) format from the continuous data archive of the INGV National Earthquake Centre (Centro Nazionale Terremoti, CNT). … more...
- Published
- 2014
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8. Fifty Years of Seismic Network Performance in Greece (1964-2013): Spatiotemporal Evolution of the Completeness Magnitude
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Arnaud Mignan and G. Chouliaras
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Earthquake catalog ,Engineering ,Geophysics ,business.industry ,Observatory ,Completeness (order theory) ,Spatiotemporal Analysis ,Modern Greek ,Magnitude (mathematics) ,Network performance ,Induced seismicity ,business ,Seismology - Abstract
The National Observatory of Athens (NOA) produces the NOA earthquake catalog since 1964. For its 50 year anniversary, we describe the evolution of the Greek seismic network by examining its performance in terms of completeness magnitude M c. Over its 50 years of existence, the earthquake catalog of Greece has improved on the basis of several network upgrades. The mid‐1960s marked the start of the modern Greek seismic network coordinated by the NOA. Since then, the earthquake catalog of NOA has been published with no interruption. Three main upgrades of the network are notable. (1) The passage from analog‐to‐digital instrumentation and processing took place in 1995. (2) The development of the Hellenic Unified Seismological Network (HUSN) took place gradually from the end of 2007 to 2011, which combined the NOA network to three university networks (Athens, Patras, and Thessaloniki). In addition, (3) the upgrade of the magnitude determination software happened in early 2011. More information about the history and characteristics of the Greek seismic network can be found in the literature (Bath, 1983; Chouliaras and Stavrakakis, 1997; Papanastassiou et al. , 2001; Papanastassiou, 2010; Roumelioti et al. , 2010; D’Alessandro et al. , 2011; Deshcherevskii and Sidorin, 2012; Chouliaras et al. , 2013). The goal of the present study is to provide the first comprehensive spatiotemporal analysis of the Greek seismic network performance in terms of completeness magnitude M c, computed using the recently proposed Bayesian magnitude of completeness (BMC) method (Mignan et al. , 2011). We additionally make an in‐depth analysis of the frequency–magnitude distribution (FMD) to validate the BMC results and to provide additional recommendations for the computation of M c. We used the NOA earthquake catalog, available at http://www.gein.noa.gr/en/seismicity/earthquake-catalogs (last accessed October 2013), and defined the study area (19° E; 29° E; 34° N; 42° N). We considered … more...
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- 2014
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9. High Probability of Foreshock Occurrence and Significant Probability of Multiple Events Associated with Magnitude >=6 Earthquakes in Nevada, U.S.A
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Craig M. dePolo
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Earthquake catalog ,High probability ,Ground motion ,Geophysics ,Magnitude (mathematics) ,Earthquake forecasting ,Earthquake swarm ,Hazard ,Seismology ,Geology ,Foreshock - Abstract
Sixty percent of magnitude 5.5 and larger earthquakes in the western Cordillera were preceded by foreshocks (Doser, 1989). Foreshocks also preceded the 2008 Wells ( M w 6.0; Smith et al. , 2011) and the 2008 Mogul ( M w 5.0; Smith et al. , 2008; dePolo, 2011) earthquakes in Nevada. Understanding foreshocks and their behavior is important because of their potential use for earthquake forecasting and foreshocks felt by communities act as a natural alarm that can motivate people to engage in seismic mitigation. A majority of larger earthquakes in Nevada had foreshocks, and several were multiple earthquakes of magnitude ≥6. Multiple major earthquakes can shake a community with damaging ground motion multiple times within a short period of time, such as happened in Christchurch, New Zealand, in 2010 and 2011 (Gledhill et al. , 2011; Bradley and Cubrinovski, 2011). Several of Nevada’s multiple events occurred within 12 hours of each other, which presents a particular hazard to emergency responders and the general public. Twenty‐three magnitude ≥6 historical earthquakes have occurred in Nevada since 1857 (Fig. 1). Earthquake catalogs used in this compilation include Slemmons et al. (1965) and Bolt and Miller (1975). Historical research and reanalysis of Nevada earthquakes have been conducted by Slemmons et al. (1965), Toppozada et al. (1981, 2000), dePolo et al. (2003), dePolo and Garside (2006), and dePolo (2012). Research on preinstrumental earthquakes consisted of systematically reviewing available earthquake catalog information and newspaper accounts. Local daily newspapers were found to be the best source of information because of their continuous nature. These records are not necessarily complete but can have important information on earthquake activity. In this study, when a local earthquake occurred beforehand and in the same general area as the event being reviewed, it was considered a foreshock. Pre‐event information varied, with less … more...
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- 2014
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10. Comment on 'A Unified Seismic Catalog for the Iranian Plateau (1900-2011)' by Mohammad P. Shahvar, Mehdi Zare, and Silvia Castellaro
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Seyed Hasan Mousavi Bafrouei, Noorbakhsh Mirzaei, and Elham Shabani
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Earthquake catalog ,Seismometer ,geography ,Tectonics ,Geophysics ,Plateau ,geography.geographical_feature_category ,De facto ,Homogeneous ,Induced seismicity ,Seismology ,Geology - Abstract
A recent paper in the March/April 2013 issue of Seismological Research Letters , “A Unified Seismic Catalog for the Iranian Plateau (1900–2011)” by Mohammad P. Shahvar, Mehdi Zare, and Silvia Castellaro (henceforth referred to as Shahvar et al. , 2013) provides a unified homogeneous earthquake catalog, for the period 1900–2011, particularly for seismic‐hazard assessment studies in Iran. They subdivide the territory of the Iranian plateau into two domains only according to seismicity to derive empirical relationships to convert the original magnitudes ( M s, m b, M L, and M N) to a uniform scale ( M w), applying standard least squares (SR) and inverted least squares (ISR) regression methods and orthogonal regression method (OR). Some contradictions in Shahvar et al. (2013) encouraged us to declare a few points. The distinction between seismotectonic zones is based on all available geologic, tectonic, geophysical, and seismological data. In other words, a seismotectonic zone is considered an area that under present‐day geodynamic regimes has an internally consistent tectonic setting and unified seismicity pattern (Ye et al. , 1993, 1995). Shahvar et al. (2013) claim that the Iranian plateau can de facto be divided into two domains only because seismicity in the Alborz and Central Iran zones show statistically undistinguishable features. In contrast, Karimiparidari et al. (2013) distinguish six seismotectonic zones based on Mirzaei et al. (1998) and Tavakoli (1996). It is noteworthy that the second author of the two concurrent inconsistent papers is in common. Based on Nowroozi (1971) and Bird et al. (1975), it is stated by Shahvar et al. (2013) that the continental Arabian shield subducts beneath the Zagros belt. However, local seismograph networks have found no reliable depths in the Zagros deeper than ∼20 km, even in places where deeper earthquakes were reported to have occurred (e.g., Niazi et al. , 1978; Tatar et al. , … more...
- Published
- 2014
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11. The True Case of the 1276 Fake Earthquake
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Paola Albini
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Earthquake catalog ,Geophysics ,Geology ,Genealogy ,Historical record ,Seismology - Abstract
In the pre-1900 time-window of earthquake catalogs, it is not unusual to come face-to-face with “fake” earthquakes erroneously listed among true ones. Such mistakes have been disclosed for many events, and their nature revealed and discussed in quite a number of papers in the last thirty years. Some discoveries of fake earthquakes originated from the revision of national catalogs ( e.g. , for France, Vogt 1979; for Italy, Guidoboni and Ferrari 1986 and Bellettati et al. 1993; for Germany, see a summary in Grunthal 2004), and others come from projects dealing with European-wide catalogs ( e.g. , Stucchi and Camassi 1997). As a consequence of these investigations, in some well-studied European regions recent catalogs have been purged of most of these mistakes. A list of fake earthquakes is now available in some regional databases (France: BRGM-EDF-IRSN/SisFrance 2010; Switzerland: Swiss Seismological Service 2002; Northern Europe: Grunthal et al. 2009), and a section devoted to fakes can be found in the European Archive of Historical Earthquake Data (AHEAD 2010). Most fakes are in fact duplications deriving from historical records that supply different locations and dates of an individual event ( e.g. , Alexandre 1991), in many cases because dates are expressed according to different calendars in use in the same period in neighboring countries. Also, fake earthquake catalog records might be the result of a mistaken interpretation of rather obscure records on other natural phenomena, such as storms or landslides ( e.g. , Alexandre 1990; Albini et al. 1990; Albini and Vogt 1992; Alexandre 1993). Among the most elusive catalog records to be unraveled as fakes are the ones originating from wrong locations of true earthquakes. Such misinterpretations of historical earthquake records might be found in 19th to early 20th century seismological literature, and from there they … more...
- Published
- 2011
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12. PAGER-CAT: A Composite Earthquake Catalog for Calibrating Global Fatality Models
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Kristin D. Marano, Trevor I. Allen, Paul S. Earle, and David J. Wald
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Earthquake catalog ,Engineering ,Geophysics ,business.product_category ,Earthquake casualty estimation ,business.industry ,Geological survey ,Landslide ,business ,Pager ,Seismology - Abstract
The compilation of a comprehensive global earthquake catalog that delivers both accurate source parameters and fatality estimates is a task that is simple in theory but challenging in practice. The necessary information is spread throughout numerous earthquake catalogs, reports, and online databases. Earthquake catalogs are created for different purposes, and consequently they excel in different areas. Some catalogs provide high-quality hypocenters while others contain carefully researched damage reports. Herein we examine published global catalogs and create PAGER-CAT, a composite global catalog of earthquake source parameters and effects. PAGER-CAT incorporates eight global earthquake catalogs and additional auxiliary data to provide comprehensive information not only for hypocentral locations, magnitudes, and human fatalities, but when available, focal mechanisms, the country of origin or the distance to the nearest landmass, local time and day of week, presence of secondary effects ( e.g. , tsunami, landslide, fire, or liquefaction) and deaths caused by these effects, the number of buildings damaged or destroyed, and the number of people injured or left homeless. The first version of the catalog is composed of more than 140 fields in which detailed event information can be recorded and currently includes events from 1900 through December 2007, with emphasis on earthquakes since 1973. The catalog was compiled for calibration and development of earthquake fatality models to be used by the U.S. Geological Survey's (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER) system. The PAGER system currently provides estimates of the number of people and the names of cities exposed to severe shaking following significant earthquakes (Earle et al. 2008; Wald et al. 2008). In the future, PAGER will produce rapid fatality estimates within approximately 20 minutes of an earthquake's occurrence anywhere on the globe, using loss models calibrated against PAGER-CAT ( e.g. , Jaiswal et al. 2008; Porter et al. … more...
- Published
- 2009
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13. Application of the EEPAS Model to Forecasting Earthquakes of Moderate Magnitude in Southern California
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David A. Rhoades
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Earthquake catalog ,Geophysics ,Scale (ratio) ,Magnitude (mathematics) ,Baseline model ,Time horizon ,Seismology ,Geology ,Event (probability theory) - Abstract
The EEPAS (Every Earthquake a Precursor According to Scale) model is a method of long-range forecasting that uses the previous minor earthquakes in a catalog to forecast the major ones. It is based on the precursory scale increase (Ψ) phenomenon, which involves an increase in the magnitude and rate of occurrence of minor earthquakes close to the source region of a major event in preparation, including most recent major earthquakes in California (Evison and Rhoades 2002, 2004). The period of time occupied by the increase scales with magnitude, but it is on the order of 15 years for an M 7 event, five years for an M 6 event, and one or two years for an M 5 event. With a one-year time horizon as specified for the Regional Earthquake Likelihood Models (RELM) testing in southern California, it is therefore feasible to consider using the model to forecast earthquakes of M 5 and above. The model has previously been fitted to the New Zealand earthquake catalog using earthquakes of magnitudes exceeding 3.95 to forecast those exceeding magnitude 5.75. It was shown to explain the data much better than a baseline model that is in principle time-invariant and has a location distribution based on proximity to the epicenters of past earthquakes. In the same form, and with the same magnitude thresholds, it was tested on California over the period 1975-2001 and again performed much better than the baseline model (Rhoades and Evison 2004). In the same form, but with magnitude thresholds one unit higher, it was tested on Japan over the period 1965-2001 and produced a similar result (Rhoades and Evison 2005), albeit with a smaller advantage over the baseline model. In order to fit well to lower magnitudes down to M 6.25, some adjustment of parameters, and in particular … more...
- Published
- 2007
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14. Modern California Earthquake Catalogs and Their Comparison
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Yan Y. Kagan
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Earthquake catalog ,Focal mechanism ,Geophysics ,Stress inversion ,Magnitude (mathematics) ,Acute stress ,Seismogram ,Seismology ,Original data - Abstract
Earthquake catalogs are primary data sources for inferring earthquake behavior, testing earthquake pattern hypotheses, and estimating seismic hazards. As in any quantitative science, understanding uncertainties is crucial to proper interpretation. Examining catalog properties will also help guide future improvements in seismic observation and catalog reporting. In an effort to create a combined earthquake catalog for southern California, I analyze several earthquake catalogs compiled in California since the 1970's to determine the accuracy of their magnitude determinations and earthquake focal mechanisms. California local earthquake catalogs were among the first to be compiled in the instrumental era (Hileman et al. , 1973; Bolt and Miller, 1975). Many catalogs are now available in California: Some earthquake lists can be extracted from instrumental global catalogs (Kagan, 2002), and several catalogs of historical events exist (Toppozada et al. , 2000, and references therein), as do a few local and regional catalogs. Many catalog compilations from original data sets and different publications have also been published. Focal mechanisms are now used for various investigations, among which studies of earthquake stress triggering ( cf . Ziv and Rubin, 2000) and stress inversion (Abers and Gephart, 2001; Hardebeck and Hauksson, 2001; Provost and Houston, 2001) are some of the most important. Moreover, catalogs with focal mechanisms are primary data sets with complete first-order information about the earthquake process; low-frequency seismograms, static displacements, and strain patterns can be computed using these data. Although global and regional focal mechanism catalogs have been compiled since the 1960's, catalogs based on compilations from individual earthquake studies have rather low and highly nonuniform accuracy of earthquake focal mechanisms (Kagan and Knopoff, 1985). Only in relatively recent catalogs of focal mechanisms does the solutions' quality allow us to analyze their routine statistical uncertainty quantitatively. Extensive and reliable earthquake catalogs with focal … more...
- Published
- 2002
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15. Blasting and Other Mining-related Activities in Kentucky: A Source of Earthquake Misidentification
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Edward W. Woolery, R. Street, and G. A. Bollinger
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Earthquake catalog ,Geophysics ,Seismic hazard ,Induced seismicity ,Seismogram ,Seismology ,Geology ,Rock blasting - Abstract
A review of seismograms from the University of Kentucky (UK) seismic network for the years 1984 through 1999 revealed that 46% of the identifiable events listed as earthquakes in national and regional catalogs for the Kentucky area were, in fact, blasts or other mining-related phenomena. Of the 109 events listed in the catalogs for the area considered, we were able to identify 39 as earthquakes, 27 as blasts, 6 as known roof falls, 5 as either an earthquake or blast (we disagreed as to which), and 32 events as inconclusive on the UK seismograms. The extent of the misidentification of blasts calls into question the reliability of such catalogs which include regions that lie outside of the seismic network used as the primary source of data for the catalog and in which there is mining activity. Inclusion of blasts and other mining-related disturbances in the earthquake catalog for Kentucky could result in a mistaken estimate of the rate of seismicity and, consequently, the seismic hazard for the state. more...
- Published
- 2002
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16. Comment on 'A Homogenous and Complete Earthquake Catalog for Northeast India and the Adjoining Region' by R. B. S. Yadav, P. Bormann, B. K. Rastogi, M. C. Das, and S. Chopra
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Ranjit Das and H. R. Wason
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Earthquake catalog ,Geophysics ,business.industry ,Yadav ,Statistics ,Magnitude (mathematics) ,Small sample ,Telecommunications ,business ,Mathematics - Abstract
In their article, Yadav et al. (2009) made two major approximations that have a significant impact on the estimates of Mw ,HRVD proxies for the catalog that they considered. The first approximation is to consider the unspecified magnitudes equivalent to MS ,ISC for all magnitude ranges, and the second relates to estimating Mw ,HRVD proxies as the average of the two M w,HRVD conversions wherever available both from mb ,ISC and MS ,ISC. They also used a small number of data pairs of Mw ,HRVD & MS ,NEIC and MS ,ISC & MS ,NEIC for estimating representative regional relationships to be used for corresponding Mw ,HRVD conversions. In this comment we examine the inaccuracy involved in these approximations and in correlations based on small sample sizes, and we propose improved regression relations and an alternative scheme for calculating the averages of Mw ,HRVD proxies. For the period 1897 to 1962, magnitudes are not specified for about 186 … more...
- Published
- 2010
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17. Reply to 'Comment on 'A Unified Seismic Catalog for the Iranian Plateau (1900-2011)' by Mohammad P. Shahvar, Mehdi Zare, and Silvia Castellaro' by Noorbakhsh Mirzaei, Elham Shabani, and Seyed Hasan Mousavi Bafrouei
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Mehdi Zare, Silvia Castellaro, Mohammad P. Shahvar, M.P. Shahvar, M. Zaré, and S. Castellaro
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Earthquake catalog ,geography ,Geophysics ,Seismic hazard ,Plateau ,geography.geographical_feature_category ,History ,Seismic catalogue ,Humanities ,Seismology - Abstract
We hereby reply to the comments of Noorbakhsh Mirzaei, Elham Shabani, Seyed Hasan Bafrouei (hereafter NES) on our paper published in Seismological Research Letters 84 (2), 233–249 (hereafter Shahvar et al. , 2013). We thank the readers for the attention given to the paper, however, we think that its purpose has been considerably misunderstood by them. As clearly mentioned in the Introduction and in the Conclusions, the aim of our paper was to provide a unified earthquake catalog for the Iranian plateau by converting the original magnitudes ( M s, m b, M L, and M N) to a uniform scale ( M w). Our aim was to estimate neither the catalog completeness nor the seismicity parameters. Our work originated from the lack of a uniform catalog of earthquakes in Iran (both for the fact that data are dispersed among several catalogs and for the fact that they report magnitudes with different scales), which makes research on seismicity and seismic hazard very difficult. Regarding the comments on the … more...
- Published
- 2014
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18. A Method for Identifying Explosions Contaminating Earthquake Catalogs: Application to the Washington Regional Earthquake Catalog
- Author
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C. D. Lindholm, R. Benson, Anthony Qamar, and Ruth S. Ludwin
- Subjects
Earthquake catalog ,Seismometer ,Daytime ,Geophysics ,Specific time ,Magnitude (mathematics) ,Seismology ,Geology - Abstract
The Washington Regional Seismograph Network (WRSN) earthquake catalog shows more earthquakes in the day than at night, probably because some local explosions are misidentified as earthquakes. We have implemented a method to help discriminate likely local blasts from local earthquakes. Probable blasts are identified based on time of occurrence (year, month and hour), magnitude, location, and depth. We have defined thirteen areas in Washington and northern Oregon, with enhanced daytime activity probably due to blasts, and have developed specific time, magnitude, and depth criteria for each area to best identify probable blasts. Except in a few regions, most of the smallest, shallowest events occurring during the day in Washington and northern Oregon are probably blasts. more...
- Published
- 1992
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19. Reply to 'Comment on 'Estimation of Seismicity Parameters for India' by S. T. G. Raghukanth' by S. K. Nath and K. K. S. Thingbaijam
- Author
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S. T. G. Raghukanth
- Subjects
Earthquake catalog ,Estimation ,Engineering ,Geophysics ,Nath ,business.industry ,Magnitude (mathematics) ,Induced seismicity ,business ,Seismology ,Web site - Abstract
The author, in Raghukanth (2010), has compiled an earthquake catalog for India and the neighboring region from various sources and used a clearly defined procedure for estimating the seismicity parameters. The obtained recurrence parameters were compared with that reported in the literature. Nath and Thingbaijam (2010, hereinafter NT) disagree with the methodology for deriving the spatial variation of seismicity parameters for India. NT's objections to the methodology are based on their theoretical interpretation and misunderstanding. I disagree with almost all of NT's comments but limit my reply to the following salient remarks. 1. I have clearly mentioned that the major portion of instrumentally located earthquakes come from the U.S. Geological Survey (http://neic.usgs.gov/) and India Meteorological Department (IMD) Web site (http:///www.imd.gov.in). 2. I agree with NT that magnitude conversion methodologies are regional in nature and incorrect conversions would yield erroneous results. No such equation has been established for Indian conditions. The magnitude conversion equations reported by Thingbaijam et al. (2008, 2009) are based on limited data and may be applicable to the northwestern and northeastern regions of India. Moreover these relations are not valid for magnitudes Mw > 6.5 due to sparse data. I used the popular magnitude conversion relations proposed by Idriss (1985 … more...
- Published
- 2010
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20. 'The Seismicity of Egypt, Arabia and the Red Sea: a Historical Review' by N. N. Ambraseys, C.P. Melville and R. D. Adams
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V.J. Murphy
- Subjects
Megalith ,Earthquake catalog ,Engineering ,Geophysics ,business.industry ,Induced seismicity ,Ancient history ,business ,Seismology - Abstract
The Seismicity of Egypt, Arabia and the Red Sea: a Historical Review N.N. Ambraseys, C.P. Melville and R.D. Adams Published by Cambridge University Press, 1994 Hardback, 0-521-39120-2, $94.95 When an earthquake catalog extends over a period of several hundred years, it obviously required considerable effort on the part of the cataloger; but when a catalog extends over millennia, it must be acknowledged as truly a monumental effort. In this publication by Ambraseys et al. , their monumental effort is all the more noteworthy because of the many historical monuments in Egypt and surrounding locales that have obviously been affected by thousands of years of earthquakes, and for which a two-thousand-plus year cataloging becomes a significant reference work for understanding the destruction of many of those monuments. Travels and explorations by this reviewer in the temple and tomb areas of Egypt and the megalithic monuments of the Golan have witnessed the remains... more...
- Published
- 1996
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21. The Events of February 4, 1883, Michigan, Indiana, and Illinois
- Author
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Norman H. Sleep
- Subjects
Earthquake catalog ,Geophysics ,Geography ,geography.geographical_feature_category ,Meteorology ,Peninsula ,Event (relativity) ,Archaeology - Abstract
The event listed for February 4, 1883, in Kalamazoo, Michigan, in the National Earthquake Catalog is attributable to the accidental railroad explosions in La Porte, Indiana, and is in fact not an earthquake. This is the second largest event attributed to the lower peninsula. No damage occurred in Kalamazoo despite reports by the Chicago press. The distribution of felt reports corresponds to that expected for an explosion in February. The event was further confused with a 5 A.M. earthquake in the Bloomington, Illinois-St. Louis area. more...
- Published
- 1981
- Full Text
- View/download PDF
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