Brilio.net - Indonesia, as a country located in the Pacific Ring of Fire, is known for its high seismic activity. With various tectonic plates meeting beneath this region, the threat of earthquakes is inevitable. Recently, the Meteorology, Climatology, and Geophysics Agency (BMKG) has again reminded the public about the potential for a megathrust earthquake, a type of earthquake that has very great destructive power.
It should be noted that the axis of the megathrust earthquake hazard is caused by an earthquake originating from the Nankai megathrust in the east off the coast of Kyushu Island, Shikoku, and Kinki, in Southern Japan. This was explained by the Head of the BMKG Earthquake and Tsunami Center, Daryono, in Jakarta on Monday, stating that the Nankai Megathrust is one of the seismic gap zones, namely an earthquake source area that has great potential but has not experienced a major earthquake in the last few decades to hundreds of years. Currently, the zone is thought to be experiencing a process of accumulating stress on the earth's crust.
"If a major earthquake in the Nankai Megathrust really occurs and causes a tsunami, then we need to be aware of this, because a major tsunami in Japan could spread to Indonesia," he said as reported by brilio.net from antaranews.com.
From the incident above, you must be aware and know what the definition of a megathrust earthquake is and its potential to occur in Indonesia from various sources, Monday (12/8).
Understanding megathrust earthquakes
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A megathrust earthquake is a type of earthquake with a very large magnitude, usually occurring in a subduction zone, which is an area where two tectonic plates meet and overlap. In this zone, one tectonic plate is pushed beneath the other plate, causing a significant buildup of tension between the two plates. Over time, this tension continues to build until it finally reaches a critical point where the accumulated energy is released in the form of a major earthquake.
The process of energy release that occurs during a megathrust earthquake often causes very strong and widespread vibrations. Because of its location under the sea or near coastal areas, this earthquake has great potential to trigger a tsunami. Ocean waves generated by a megathrust earthquake can travel quickly and cause serious damage in coastal areas, even thousands of kilometers from the epicenter.
The potential damage caused by a megathrust earthquake is not only limited to the area around the epicenter, but can also have a wide impact, including on infrastructure and people's lives. Therefore, understanding megathrust earthquakes and the risks that accompany them is very important to reduce the impact of disasters and increase community preparedness in facing the possibility of this major earthquake.
Potential for megathrust earthquakes in Indonesia
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According to the journal article "The potential for megathrust earthquakes in the Sunda Strait region, Indonesia" published in Earth and Planetary Science Letters, Widiyantoro (2018) revealed that Indonesia is in an area that is very prone to megathrust earthquakes, especially in the subduction zone that stretches along the Sumatra, Java, and Nusa Tenggara regions. This study highlights the importance of understanding the geodynamics of this region, where the meeting of tectonic plates creates great potential for very large earthquakes.
The potential for megathrust earthquakes in Indonesia is greatly influenced by the continuous movement of tectonic plates and the accumulation of stress that occurs beneath the earth's surface. In a subduction zone, one tectonic plate is pushed beneath another, creating pressure that continues to increase over time. When this tension is finally released, it can trigger a megathrust earthquake with a very large force, resulting in significant impacts on the affected area.
The scientific studies presented in this journal show that several regions in Indonesia have the potential for megathrust earthquakes with magnitudes that can reach more than 8.0 on the Richter scale.
However, if we look at the explanation from Daryono as the Head of the BMKG Earthquake and Tsunami Center, he explained that Indonesia does not need to worry because BMKG has been monitoring, processing, and disseminating earthquake information and tsunami early warnings that are increasingly fast and accurate as a step of anticipation and mitigation.
Please note, BMKG has the InaTEWS (Indonesia Tsunami Early Warning System) system which functions to immediately disseminate information about earthquakes and tsunami early warnings throughout Indonesia, as well as monitor earthquake and tsunami activity in the Japanese Nankai Megathrust zone and its surroundings in real-time.
The concerns of Japanese scientists regarding the Nankai Megathrust are currently in line with the concerns of Indonesian scientists, especially regarding the M8.7 Sunda Strait Seismic Gap Megathrust and the M8.9 Mentawai-Suberut Megathrust.
BMKG believes that the possibility of a major earthquake occurring in these two megathrust segments is only a matter of time, considering that these two regions have not experienced a major earthquake for hundreds of years.
To anticipate this, BMKG continues to provide education, training, mitigation, drills, evacuation, based on tsunami modeling. This education is given to local governments, related agencies, communities, coastal tourism business actors, coastal industries and critical infrastructure of coastal ports and airports. This education is packaged in activities such as the Earthquake and Tsunami Field School (SLG), BMKG Goes To School (BGTS) and the Formation of a Tsunami Preparedness Community (Tsunami Ready Community).
"We hope that efforts to mitigate earthquake and tsunami disasters can minimize the risk of disaster impacts that may occur, even to the point of creating zero victims," he said.