Publication Date:
2021-03-31
Description:
On 21 August 1962 an earthquake sequence set off near the city of Benevento, in Italy's southern Apennines.
Three earthquakes, the largest having Mw 6.1, struck virtually the same area in less than 40 min (at 18:09,
18:19 and 18:44 UTC, respectively). Several historical earthquakes hit this region, and its seismic hazard is accordingly
among the highest countrywide. Although poorly understood in the past, the seismotectonics of this
region can be revealed by the 1962 sequence, being the only significant earthquake in the area forwhichmodern
seismograms are available.
We determine location, magnitude, and nodal planes of the first event (18:09 UTC) of the sequence. The focal
mechanismexhibits dominant strike-slip rupture along a north-dipping, E-W striking plane or along a west-dipping,
N-S striking plane. Either of these solutions is significantly different fromthe kinematics of the typical large
earthquakes occurring along the crest of the Southern Apennines, such as the 23 November 1980 Irpinia earthquake
(Mw 6.9), caused by predominant normal faulting along NW-SE-striking planes.
The epicentre of the 21 August 1962, 18:09 event is located immediately east of the chain axis, near one of the
three north-dipping, E-W striking oblique-slip sources thought to have caused one of the three main events of
the December1456 sequence (Io XIMCS), the most destructive events in the southern Apennines known to date.
Wemaintain that the 21August 1962, 18:09 earthquake occurred along the E-Wstriking fault systemresponsible
for the southernmost event of the 1456 sequence and for two smaller but instrumentally documented events that
occurred on 6May 1971 (Mw 5.0) and 27 September 2012(Mw 4.6), further suggesting that normal faulting is not
the dominant tectonic style in this portion of the Italian peninsula.
Description:
Published
Description:
375-384
Description:
2T. Tettonica attiva
Description:
JCR Journal
Description:
open
Keywords:
1962 Irpinia earthquake
;
Multiple earthquake
;
Focal mechanism
;
Strike-slip faulting
;
Active tectonics
;
Seismic hazard
;
04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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