Characterization of Seismicity and Seismic Hazard in the Coquimbo Region, Chile: A Probabilistic Study

• Published in: Pure and applied geophysics Vol. 181; no. 5; pp. 1427 - 1454
• Main Authors: Ojeda, Valentina, Vega-Jorquera, Pedro, de la Barra, Erick, Palma-Chilla, Luis, Vidal, Luis, Saavedra, José, Pizarro, Alfredo
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-05-2024; Springer Nature B.V
• Subjects: Cost analysis; Earth and Environmental Science; Earth Sciences; Earthquakes; Frequency distribution; Geological hazards; Geophysics/Geodesy; Hazard assessment; Mathematical models; Physics; Seismic activity; Seismic hazard; Seismicity; Statistical analysis; Statistical mechanics; Statistical models; Chile; Seismic hazard; Frequency-magnitude and frequency-interevent-time distributions; Nonextensive statistics; Mathai’s model
• ISSN: 0033-4553; 1420-9136
• DOI: 10.1007/s00024-024-03474-4

In order to seismically characterize Chile’s northern Coquimbo Region, data from 2003 to 2020 were considered. The region was divided into 30 zones of
0
.
5
∘
latitude and
0
.
5
∘
longitude and non-extensive statistical physics was used. Both, the Sotolongo–Costa–Posadas (SCP) and Mathai models were deployed to analyze the magnitude-frequency distribution. A sub-division into cells of the catalog allowed to demonstrate that systems with value of
q
∼
1
present exponential behavior, while it was expected to obtain
q
>
1
, by superimposing sub-systems supporting the superstatistical model. Thus, by subdividing the Coquimbo region into south and north, we found that in both zones the entropic index is greater than 1,
q
>
1
, However, in the southern zone the long-range effects are greater than in the north, according to the value obtained, which means both sectors are well described under a nonextensive statistical model, be it the SCP model or the Mathai one. The entropic index is
q
>
1
and in both cases
R
2
>
0.99
. As the region is considered as a whole, the nonextensive statistical distribution is the more adequate one. With respect to probabilistic seismic hazard assessment, Mathai’s model proved to have the better fit. Thus, the frequency-interevent time distribution was used for different limit magnitude values. Our analysis showed that the probability occurrence of a seismic event in the region’s north is lower than in the south considering the same period. In the north the behavior is of Poissonian type.