Publication Date:
2017-04-04
Description:
The M ∼ 7 1915 Fucino (Central Italy) earthquake represents one of the most destructive
seismic events ever occurred in the Italian Peninsula. Several seismogenic faults have been
proposed in the past decades as the source of the earthquake by means of different approaches
and techniques that lead to a variety of speculations about the source mechanism and the fault
location, often contrasting with one another. The 1915 earthquake produced a remarkable data
set of 73 coseismic hydrological changes in the near and intermediate field that consist in variation
of the flow of streams and springs, liquefaction, rise of water temperature and turbidity.
In this paper, we study the coseismic water level changes induced by the 1915 earthquake in
the near field to provide convincing clues on the geometry of the earthquake causative fault.
We model the coseismic strain field induced by seventeen individual faults proposed through
different approaches, and compare its pattern with the distribution of streamflow changes.
We find: (i) clues on the most probable geometry of the earthquake causative fault. Best fits
between modelled deformation and observed data are displayed by sources (derived by geological
or seismological data) that share several distinctive features, as they are ∼135◦-striking,
SW-dipping, 25–30-km-long normal faults located along the eastern side of the Fucino basin.
These data point to the Serrone Fault and the Parasano Fault as the most likely causative structures
and support the hypothesis that the coseismic ruptures observed in the field represented
primary surface faulting. On the contrary, our calculations show that the Pescina Fault and the
Ventrino Fault are secondary faults from the perspective of the hydrological response. Finally,
one of the best scoring potential sources (from geological data) is a multifaulting system that
considers the presence, in the central-western part of the basin, of fault splays synthetic and
antithetic to the main seismogenic structures; therefore, we infer for these splays a possible
active involvement in a 1915-like seismogenic process; (ii) evidence against a number of
seismogenic structures that were previously associated with the earthquake. In particular, the
plots of coseismic strain induced by sources uniquely derived by macroseismic or geodetic
data prove to be inconsistent with the polarities of the hydrological signatures. Also, sources
mainly characterized by reverse faulting and/or by right-lateral strike-slip component are discarded
and (iii) as a final remark, we maintain that the study of the hydrological signatures of
earthquake strain can offer an alternative tool in the investigation of the historical seismicity,
to estimate the focal mechanism of major earthquakes capable of giving rise to a consistent
data set of hydrological data.
Description:
Published
Description:
1374-1388
Description:
2T. Tettonica attiva
Description:
JCR Journal
Description:
restricted
Keywords:
1915 Fucino earthquake
;
04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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