Publication Date:
2017-04-04
Description:
The Italian seismic catalog (Rovida et al., 2011) portrays a significant
gap of seismicity in the Pollino Range area, the southernmost
segment of the southern Apennines at the boundary
with the Calabrian arc. In this region, the only significant seismic
event of the instrumental era occurred in 1998 north of the
Pollino Range (Mw 5.6, Fig. 1). No seismic event with intensity
greater than VIII on the Mercalli–Cancani–Sieberg (MCS) scale
is present in the historical records, whereas strong earthquakes
occurred immediately north (1836 M 6.0; 1857 M 7.0) and
south (1184 M 6.7; 1836 M 6.2) of the area (Fig. 1). However,
geologic data (Bousquet, 1973; Russo and Schiattarella, 1992)
have shown clear evidence ofQuaternary faulting along two major
normal seismogenic faults, the Pollino and the Castrovillari
faults. Paleoseismological data (Michetti et al., 1997;Cinti et al.,
1997, 2002) recognized the occurrence of large magnitude
events during medieval times along those two faults, but no trace
is left of these major events in the historical record.
In the case of the Pollino area, the discrepancy between
true seismic history and recorded seismic history is due to a
combination of a documentary gap of the historical sources
(Scionti et al., 2006) and to the low population and scarcity
of settlements in the epicentral area (D’Addezio et al., 1995;
Cinti et al., 1997). Furthermore, there is the sound possibility
that such documentary limitation also might affect moderate
(M 5–6) earthquakes, thus providing the opportunity for new
assessments that could re-estimate their sizes. Noticeable recent
examples of this come from Scionti et al. (2006), with the reestimation
to Mw 6.2 of an earthquake that occurred 100 km
southeast of the Pollino region, from Tertulliani et al. (2012)
for the 1762 earthquake close to L’Aquila, and from Azzaro
et al. (2007) for northeastern Sicily. We want to emphasize
that there is recent growing interest in the question of reestimating
the sizes of historical earthquakes (see Rong et al.,
2011; Hough, 2013). Therefore, reducing the uncertainties in
the locations and sizes of seismic events for areas like Pollino
can be an important contribution toward a clearer picture of
the seismic potential and the distribution of earthquake recurrence
times that can affect the seismic hazard of a territory.
The first attempts at in-depth analyses of the historical
seismicity in the Pollino seismic gap date back to the first half
of the 1990s (Storia Geofisica Ambiente [SGA], 1994; Valensise
et al., 1994; Guidoboni and Mariotti, 1997), whereas more
recent developments are by SGA (2000), Camassi and Castelli
(2004), and Castelli and Camassi (2005). The seismic histories
(the list of earthquakes affecting a site during historic time) of
towns and villages of the area (Locati et al., 2011) do not
contain earthquakes that occurred before A.D. 1600, neither
local nor remote, which could have affected such localities. The
oldest traces of earthquakes are associated with the 1638 M 7
event that occurred in central Calabria ∼100 km south of the
Pollino area and produced damage in Castrovillari. The more
ancient event documented in the study area is the 1693 earthquake,
which was listed for the first time in a catalog in 2007
(Guidoboni et al., 2007). In this study, we focus on this latter
event, which also appears as the strongest shock in the region
and is characterized by a relative scarcity of information and
few intensity datapoints. We gathered all potential primary
sources of information available for the 1693 earthquake in
the attempt to improve its intensity map. We also address two
further issues in the reappraisal of the 1693 earthquake: (1) the
temporal coincidence between 8 January 1693 Pollino earthquake
and its aftershocks and 9–11 January 1693 catastrophic
earthquakes of eastern Sicily, along with the consequent quest
for a correct attribution of the information regarding the two
seismic sequences; and (2) the occurrence in October 2012
(following a sequence of small earthquakes lasting three years)
of an Mw 5.3 mainshock, which is by far the strongest event in
the instrumental era in the area.
Description:
Published
Description:
743-751
Description:
3T. Pericolosità sismica e contributo alla definizione del rischio
Description:
JCR Journal
Description:
restricted
Keywords:
Pollino
;
1693 earthquake
;
04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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