IAG-IASPEI 2017

Presentation information

Oral

IASPEI Symposia » S04. Historical and macroseismic studies of earthquakes

[S04-1] Historical and macroseismic studies of earthquakes I

Thu. Aug 3, 2017 8:30 AM - 10:00 AM Room 403 (Kobe International Conference Center 4F, Room 403)

Chairs: Toshitaka Baba (Tokushima University) , Paola Albini (Istituto Nazionale di Geofisica e Vulcanologia)

9:45 AM - 10:00 AM

[S04-1-05] The 1895 Ljubljana earthquake: can the intensity data points discriminate which one of the nearby faults was the causative one?

Lara Tiberi1, Giovanni Costa1, Petra Jamsek Rupnik2, Ina Cecic3, Peter Suhadolc4 (1.Department of Mathematics and Geosciences, University of Trieste, Trieste, Italy, 2.Geological Survey of Slovenia, Dimiceva ul. 14, SI-1000 Ljubljana, Slovenia, 3.Agencija RS za okolje, ARSO, Ljubljana, Slovenia., 4.Department of Mathematics and Geosciences, University of Trieste, Trieste, Italy, retired)

The earthquake (Mw 6) that occurred in the central part of Slovenia on the 14th of April, 1895, affected a broad region, causing deaths, injuries and destruction. This event was much studied but not fully explained, in particular its causative source model.
The aim of this work is to contribute to the identification of the seismogenetic source of this destructive event, estimating peak ground parameters through the use of different GMPEs and computing a series of ground motion scenarios based on various fault models and nucleation points in the surroundings of Ljubljana: Vic, Zelimlje, Borovnica, Vodice, Ortnek, Misjedolski, Dobrepolje faults. The synthetic seismograms, at the basis of our computations, are calculated using the multi-modal summation technique and a kinematic approach for extended sources. In particular, we compute the maximum peak ground velocity value at 1 Hz because at high frequencies seismograms are strongly influenced by the short-wavelength complexities of the medium.
The qualitative and quantitative comparison of these simulations with the intensity field allows us to discriminate between various sources and configurations. The quantitative validation of the seismic source is done using an appropriate regression law, expressly calculated for this study. The main strong earthquakes used for this calculation are the two Bovec earthquakes (1998, 2004), the Aquila event of 2009, the two Emilia ones of 20th and 29th of May, 2012 ant the last Amatrice event of 24th of August 2016.
This study allows us to identify the most probable causative source model of this event, contributing to the improvement of the seismotectonic knowledge of this region.