第69回統計地震学セミナー / The 69th Statistical Seismology Seminar

Date&Time
2018年3月20日(火)
/ 20 March, 2018 (Tue) 13:30 – 14:30

Admission Free,No Booking Necessary

Place
統計数理研究所 4階ラウンジ
/ 4F Lounge @ The Institute of Statistical Mathematics
区切り線
Speaker
Elisa Varini
(CNR-Istituto di Matematica Applicata e Tecnologie Informatiche)
Title
Identification of earthquake clusters in Northeastern Italy by different approaches
Abstract

Earthquakes do not occur randomly in space and time; rather, they tend to group into clusters that can be classified according to their different properties, presumably related to the specific geophysical properties of a seismic region. Thus, we aim at exploring the spatio-temporal features of earthquake clusters in North- eastern Italy, based on a systematic analysis of robustly and uniformly detected seismic clusters reported in the local bulletins, compiled at the National Institute of Oceanography and Experimental Geophysics since 1977. First, data are analysed by a method for detection of earthquake clusters, based on “nearest-neighbor dis- tances” between events in space-time-energy domain (Baiesi and Paczuski, 2004). Then they are analysed by applying a stochastic declustering algorithm based on ETAS model (Zhuang, Ogata, and Vere-Jones, 2002), in which events are associ- ated to clusters in accordance with their estimated probability distributions. Both methods allow for a robust data-driven identification of seismic clusters, and permit to disclose possible complex features in the internal structure of the identified clus- ters. By comparing these approaches, we take advantage of a different description of the clustering process in order to assess consistency and reliability of the findings. We found some evidence that swarm-like sequences are mostly associated with the north-western part of the study region, while burst-like sequences tend to occur in the south-eastern part of it.

Key words: earthquake clustering, nearest-neighbor distance, stochastic decluster- ing, ETAS model