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Homogenization in terms of M (sub W) of local magnitudes of Italian earthquakes that occurred before 1981

Barbara Lolli, Paolo Gasperini and Alessandro Rebez
Homogenization in terms of M (sub W) of local magnitudes of Italian earthquakes that occurred before 1981
Bulletin of the Seismological Society of America (February 2018) 108 (1): 481-492


In the last two decades, several studies addressed the revaluation and homogenization of the Italian instrumental seismic catalog, but all of them refer to the time interval from 1981, that is, the starting year of the Catalogo Strumentale dei Terremoti Italiani (CSTI). At the time, the CSTI was conceived as the continuation of the catalog of the Progetto Finalizzato Geodinamica (PFG) but, over time, the PFG catalog was almost totally forgotten, and presently it is even difficult to obtain because it is not provided by any website. In this work, we integrate a genuine copy of PFG, with additional locations from the bulletins of the Istituto Nazionale di Geofisica (ING, now known as INGV) and of the International Seismological Centre (ISC) and with local magnitudes from two couples of Wood-Anderson (WA) seismometers operational in Italy in the 1970s and 1980s, mostly derived from a careful scrutiny of paper bulletins of the Osservatorio Geofisico Sperimentale (OGS) and of the ING. We restrict our analysis to the time interval from 1960 to 1980 because, based on various evidence, we can infer that within such period most instrumental magnitudes reported by the PFG catalog are reasonably coherent with the Richter's definition. Magnitudes provided by WA stations and other data sources are calibrated with respect to M (sub w) by general orthogonal regressions. The final catalog from 1960 to 1980 contains 8536 earthquakes, of which we compute a true or proxy M (sub w) magnitude with related uncertainty for 6407. The analysis of the frequency-magnitude distribution indicates completeness for about M (sub w) > or =4.0. This work extends the time coverage of the Italian instrumental catalog to about 55 yrs before the present, allowing the statistical study of some important seismic periods that occurred, for example, in 1962 (Irpinia), 1968 (Belice Valley), 1976 (Friuli), 1979 (Umbria), and 1980 (Irpinia).

ISSN: 0037-1106
EISSN: 1943-3573
Serial Title: Bulletin of the Seismological Society of America
Serial Volume: 108
Serial Issue: 1
Title: Homogenization in terms of M (sub W) of local magnitudes of Italian earthquakes that occurred before 1981
Affiliation: Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna, Bologna, Italy
Pages: 481-492
Published: 201802
Text Language: English
Publisher: Seismological Society of America, Berkeley, CA, United States
References: 42
Accession Number: 2018-052127
Categories: Seismology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables, sketch map
N36°30'00" - N47°30'00", E06°30'00" - E19°00'00"
Secondary Affiliation: Universita di Bologna, ITA, ItalyIstituto Nazionale di Oceanografia e Geofisica Sperimentale, ITA, Italy
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Abstract, Copyright, Seismological Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 2018
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