High-frequency maximum observable shaking map of Italy from fault sources

Abstract

We present a strategy for obtaining fault-based maximum observable shaking (MOS) maps, which represent an innovative concept for assessing deterministic seismic ground motion at a regional scale. Our approach uses the fault sources supplied for Italy by the Database of Individual Seismogenic Sources, and particularly by its composite seismogenic sources (CSS), a spatially continuous simplified 3-D representation of a fault system. For each CSS, we consider the associated Typical Fault, i.e., the portion of the corresponding CSS that can generate the maximum credible earthquake. We then compute the high-frequency (1-50 Hz) ground shaking for a rupture model derived from its associated maximum credible earthquake. As the Typical Fault floats within its CSS to occupy all possible positions of the rupture, the high-frequency shaking is updated in the area surrounding the fault, and the maximum from that scenario is extracted and displayed on a map. The final high-frequency MOS map of Italy is then obtained by merging 8,859 individual scenariosimulations, from which the ground shaking parameters have been extracted. To explore the internal consistency of our calculations and validate the results of the procedure we compare our results (1) with predictions based on the Next Generation Attenuation ground-motion equations for an earthquake of M w 7.1, (2) with the predictions of the official Italian seismic hazard map, and (3) with macroseismic intensities included in the DBMI04 Italian database. We then examine the uncertainties and analyse the variability of ground motion for different fault geometries and slip distributions.

On the complexity of earthquake sequences: a historical seismology perspective based on the L'Aquila seismicity (Abruzzo, Central Italy), 1315-1915

“…Although the progressive worsening of damage belongs to the common perception of all those who lived through a devastating earthquake sequence, we suspect many seismologists and earthquake engineers tend to forget that the damage accumulated at the end of a complex earthquake sequence will inevitably -or at least very likely -be much larger than expected after the first large shock. Even deterministic earthquake scenarios tend to focus exclusively on the effects of one shock at a time -perhaps for fear that they may end up being too severe -and to express the ground motion only through peak ground acceleration (see for example Zonno et al 2012) rather than in terms of the total duration of strong ground shaking or using other parameters of engineering interest. We believe that historical evidence of earthquake complexity may help engineering seismologists and structural engineers focusing on how the performance of a building will be worsened by subsequent strong earthquakes on adjacent faults.…”

Seismic zoning of Tabriz area by stochastic finite fault model considering site-specific soil effects

“…For instance, Scandella et al (2011) investigated the earthquake scenario in Vicoforte, Italy, applying the kinematic source developed by Hisada & Bielak (2003) and the stochastic finite fault. Similarly, Zonno et al (2012) presented the high-frequency maximum observable shaking map of Italy for the fault source. Besides, Yazdani & Kowsari (2013) provided the earthquake ground-motion prediction equation for northern Iran using the same method.…”