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From mapped faults to fault-length earthquake magnitude (FLEM): a test on Italy with methodological implications.

From mapped faults to fault-length earthquake magnitude (FLEM): a test on Italy with methodological implications.

Authors :
Trippetta, Fabio
Petricca, Patrizio
Billi, Andrea
Collettini, Cristiano
Cuffaro, Marco
Lombardi, Anna Maria
Scrocca, Davide
Ventura, Giancarlo
Morgante, Andrea
Doglioni, Carlo
Source :
Solid Earth. 2019, Vol. 10 Issue 5, p1555-1579. 25p.
Publication Year :
2019

Abstract

Empirical scaling relationships between fault or slip dimensions and earthquake magnitudes are often used to assess the maximum possible earthquake magnitude of a territory. Upon the assumption of the reactivability of any fault, the earthquake magnitudes derived from the surface fault length (FLEM) are compared at the national scale in Italy against catalogued magnitudes. FLEMs are obtained by considering a comprehensive fault dataset regardless of fault age, stress field orientation, strain rate, etc. In particular, (1) a comprehensive catalogue of all known faults is compiled by merging the most complete databases available; (2) FLEM is then derived from fault length; and (3) the resulting FLEMs are compared (i.e. the mathematical difference) with catalogued earthquake magnitudes. Results show that the largest FLEMs as well as the largest differences between FLEMs and catalogued magnitudes are observed for poorly constrained faults, mainly inferred from subsurface data. It is suggested that these areas have to be further characterized to better estimate fault dimension and segmentation and hence properly assess the FLEM. Where, in contrast, the knowledge of faults is geologically well constrained, the calculated FLEM is often consistent with the catalogued seismicity, with the 2 σ value of the distribution of differences being 1.47 and reducing to 0.53 when considering only the Mw≥6.5 earthquakes. Our work highlights areas, in Italy, where further detailed studies on faults are required. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
18699510
Volume :
10
Issue :
5
Database :
Academic Search Index
Journal :
Solid Earth
Publication Type :
Academic Journal
Accession number :
139677344
Full Text :
https://doi.org/10.5194/se-10-1555-2019