Civil Engineering and Architecture 8(6): 1491-1496, 2020
DOI: 10.13189/cea.2020.080630
http://www.hrpub.org
Triggered Seismicity in Northern Algeria from a
Statistical Modeling
L. Amir
*
, L. Abdessamed
Department of Geophysics, Faculty of Earth Sciences and Geography, USTHB, BP 32, Bab Ezzouar, 16111,Algiers, Algeria
Received October 12, 2020; Revised December 10, 2020; Accepted December 20, 2020
Cite This Paper in the following Citation Styles
(a): [1] L. Amir, L. Abdessamed , ”Triggered Seismicity in Northern Algeria from a Statistical Modeling,” Civil Engineering and Architecture, Vol. 8, No. 6,
pp. 1491-1496, 2020. DOI: 10.13189/cea.2020.080628.
(b): L. Amir, L. Abdessamed , (2020). Triggered Seismicity in Northern Algeria from a Statistical Modeling. Civil Engineering and Architecture,
8(6), 1491-1496. DOI: 10.13189/cea.2020.080628.
Copyright ©2020 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of
the Creative Commons Attribution License 4.0 International License
Abstract Seismic clustering raises challenging questions
concerning the nucleation process in regions marked by
active faults. In this paper, we present a stochastic modeling
approach to identify background and triggered seismicity
in Northern Algeria. To perform the seismic clustering, we
used the etasFLP package from the CRAN (Comprehensiv
Archive Network) in R. The model was calibrated by testing
and combining the FLP (Forward Likelihood Predictive) and
ML(Maximum Likelihood) method for the non-parametric
and the parametric parameters that describe the intensity
function. On the whole, the results show that the greater
contribution for events comes from the triggered earthquakes.
The etasFLP package is suitable to describe the pattern for
main shock and aftershocks sequences. Nevertheless, the
discrepancies concern here the spatial distribution of the
triggered events. In fact, the present modeling indicates the
necessity to add, during the computation, additional terms for
coefficients that represent external factors that influence the
neighboring stress and would cause triggered events. More-
over, a database with more events could provide an accurate
modeling that would represent the distribution between the
background and the triggered events. The Northern Algeria
is the location for diverse source of tremors and therefore,
there is a need to identify clearly man-made activities that
might trigger seismic sequence. The present work aims at
proposing the application of the ETAS model for such purpose.
Keywords Earthquakes, Likelihood, Modeling, Northern
Algeria, Induced Seismicity, Etasflp, Background Seismicity,
Intensity Function
1 Introduction
Seismic clustering helps to define whether an event is
independant or triggered and generated by either aftershocks
or the increase of the pore pressure due to the presence of
fluids.The rupture mechanism for an active fault is related to
the static stress condition within a fault system.The tectonic
loading is known to be the main mechanism that determines
a background seismicity. In this case, the earthquakes are
independant. On the other hand, the stress transfer to the
neighboring region after the main shock or the stress increases
related to the pore fluid pressure when fluids are migrating
within the cracks or the active fault determines the induced or
triggered seismicity.
Located between the converging Eurasian and African
tectonic plates, the collision setting of Northern Algeria is
prone to moderate to important and destructive earthquakes
with magnitudes up to 7.5. Induced seismicity has already
been identified as a potential source of a list of earthquakes
in northern Algeria. Active faults related folds in the region
(Chott El Hammam) have been mapped and considered
potential locations for fluids migration related to hydrothermal
springs [1].
On the 1st of January 1965, the Hodna plains were struck by a
devastating earthquake, the largest event ever recorded and felt
in the region at that time (Io= VIII (MSK); Ms=5.4) [2]. While
describing the damage and the casualty distribution, Benouar
[2] reported that a witness ”saw the sky red as a blaze”. He
added that ”the atmosphere was smelling sulphur gas”. On
February 1960, another earthquake hit the Melouza region
(Beni-Ilmane) near the Djebel Choukchott (Io = VIII (MSK))
[2]. In addition to the reported damage and casualty distribu-