Page 254 - Contributed Paper Session (CPS) - Volume 4

CPS2219 Hasih P. et al.
The management of earthquake disasters is still being studied in terms of
both seismology and stochastic aspects. One of the stochastic model that
describes earthquake’s phenomenon is a point process. In this process,
earthquakes are seen as a collection of random points in a space, with each
point stating the time and / or location of the earthquake (Sunusi et al. [4]). In
the point process to find out the intensity of events per unit of time can be
known through the conditional intensity function (Ogata [6]). The conditional
intensity function is the probability of the occurrence of an event in a very
small time interval with the conditions of the events in the previous time.
In the seismology, elastic rebound theory still has a major role. The elastic
rebound theory that proposed by Reid is a classic theory for earthquakes. This
theory showed that the elastic pressure in the seismic region accumulates due
to tectonic plate movement and is released when the pressure exceeds the
limit of plate strength. This theory also showed that large earthquakes are
usually followed by passive periods, whereas in fact large earthquakes are
followed by active periods and sometimes followed by earthquakes that have
nearly the same magnitude (Lu et al. [1]).
Vere-Jones [2] proposed a stress release model, which is a stochastic
version of the elastic rebound theory. The stress release model considers the
pressure that increases in an area and the pressure had been released during
an earthquake in a certain period. In 1994, Zheng and Vere-Jones [5] applied
a stress release model to earthquake data in China, Iran, and Japan. One of the
interesting phenomenon to be observed in his research is that the biggest
event is often followed by other major events that are located far enough from
the first event. In the earthquake analysis, an area has interaction with other
regions. Zheng and Vere-Jones [5] noted several clues to the grouping of
treatment transfers of pressure and interaction interregions. Transfer of stress
and interaction interregions cannot be considered in the stress release model.
The model linked stress release is the development of the stress release model
proposed for spatial analysis of the earthquake’s occurrence through the
transfer of pressure over large areas of the earth's crust.
Jawa, Bali and Nusa Tenggara are part of Indonesia's seismotectonics. This
area is traversed by Mediterranean mountains and there is a subduction zone
due to a meeting between the Eurasian Plate and the Indo-Australian Plate.
The limit of this meeting is in the form of an Oceanic Trench in the south of
the cluster of Java, Bali and Nusa Tenggara Islands. This condition causes Java,
Bali, and Nusa Tenggara to have high seismic activity.
Through a linked stress release model, it can be used to analyze stress
transfers and interactions between regions on the three islands. In the June-
August 2018 a series of earthquakes occurred on the islands of Lombok and
Sumbawa which were felt to reach Bali and some parts of Java. The biggest
earthquake was a magnitude of 7.2 SR which occurred on 5th August 2018

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