A Fast Procedure to Estimate the Prevailing Rupture Propagation Direction and How It Applies to the 2016-2017 Central Italy Seismic Sequence
We present a new approach aimed to generalize the statistical procedure proposed by Calderoni et al., (2017) to estimate the prevailing direction of rupture propagation in a given region during a seismic sequence. We apply this procedure to the strongest earthquakes (Mw ≥ 4.4) of the 2016-2017 Central Italy seismic sequence and compare our results with other studies.The method is based on the Empirical Green Function (EGF) deconvolution method. The main advantage of our method is that it is conceptually simple and fast (near real-time speeds) and can be applied to any active seismic area. Results show heterogeneity of rupture directivity along the activated fault system with a complex pattern even if most of the studied events have similar focal mechanisms. However, homogeneous pattern in rupture directivity is observed along the activated fault system and the preferred trend of the rupture propagation is in large part controlled by pre-existing structural discontinuities, i.e., the NW-SE faults. Therefore, we suggest that pre-existing structural discontinuities may control the directivity in the way that such discontinuities represent weakness zone, i.e., zones affected by a bi-material fault interface. We also discuss the possible role of fluids as a cause of bi-material and propose an interpretation of our results based on the role of fluids in the studied sequence as reported in literature.
Furthermore, we investigated a possible control of rupture directivity on the location of immediate aftershocks. We calculated the cumulative number of events, which occurred in the forward, backward and orthogonal rupture propagation direction, before and after the occurrence of events and found that for the analyzed events immediate seismicity mainly appears to be correlated with rupture directivity along the pre-existing structural discontinuities.
Session: Earthquake Source Processes at Various Scales: Theory and Observations [Poster]
Type: Poster
Room: Evergreen Ballroom
Date: 4/21/2022
Presentation Time: 08:00 AM Pacific
Presenting Author: Giovanna Calderoni
Student Presenter: No
Additional Authors
Giovanna Calderoni Presenting Author Corresponding Author giovanna.calderoni@ingv.it Istituto Nazionale di Geofisica e Vulcanologia Rome Headquarters |
Rita Di Giovambattista rita.digiovambattista@ingv.it Istituto Nazionale di Geofisica e Vulcanologia |
Guido Ventura guido.ventura@ingv.it Istituto Nazionale di Geofisica e Vulcanologia |
|
|
|
|
|
|
A Fast Procedure to Estimate the Prevailing Rupture Propagation Direction and How It Applies to the 2016-2017 Central Italy Seismic Sequence
Category
Earthquake Source Processes at Various Scales: Theory and Observations
Description