Publication Date:
2017-04-04
Description:
The main goal of Task 6 is the computation of the bedrock and site seismic scenarios
in the Gubbio town and in the Gubbio basin (Central Italy). This area represents one
of the prediction case studies, planned in the framework of Project S3 which aims at
simulating ground shaking scenarios for moderate magnitude earthquakes.
Deterministic shaking scenarios, described in this report, are computed for the
Maximum Credible Earthquake. This is associated with two sources capable of
generating an earthquake with M equal to 6 and located at about 10km from the
sites.
Starting from these sources bedrock shaking scenarios at different level of complexity
are computed by ground motion prediction equations (scenarios of level 0), high
frequency (f〉0.5Hz) simulations (scenarios of level 1) and broad band (0-20 Hz)
simulations (scenarios of level 2). However since many sites have to be simulated for
accurately sampling the basin, the bedrock ground motions for evaluating the
seismic response of the valley are generated at level 1.
For four test sites a comparison between time series computed at different levels of
complexity have been performed in order to verify the approximations introduced in
level 1.
Before computing the predicted shaking scenarios, we evaluate the modelling
capability of the adopted simulation techniques reproducing the observed ground
motions occurred during the 1984 Gubbio earthquake (M 5.7).
Finally we apply the probabilistic-deterministic approach for a characteristic
earthquake scenario proposed by Convertito et al. (2006) to perform hazard analysis
considering the two seismogenic faults at three sites of interest in the Gubbio area
(paragraph 3.3). In this way, respect to the deterministic approach, we produce
‘dynamic shaking scenarios’ introducing the time variable.
The shaking scenarios generated in the Gubbio area allow us to show how the
prediction of the ground motion can be tackled using different methodologies and
which strategy should be followed to select mean shaking scenario. As the available
information increases, we could gradually adopt approaches more and more
sophisticated and provide shaking scenarios that account for specific effects related
to the source and propagation (e.g., directivity, radiation pattern distribution,…).
Furthermore, the adoption of different approaches allows a cross check of the results
guaranteeing the reliability of the ground motion estimates.
Description:
Progetto INGV-DPC S3 “Scenari di scuotimento in aree di interesse prioritario e/o strategico”
Description:
Published
Description:
4.2. TTC - Scenari e mappe di pericolosità sismica
Description:
open
Keywords:
Shaking scenarios
;
Gubbio
;
04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
report
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