Gempa Megathrust Guncang Pacitan, Satu Orang Tewas

Summary

A 6.4 magnitude tectonic earthquake hit Pacitan, East Java, early Friday morning. BMKG's Plh. Director of Earthquakes and Tsunamis, Mr. Wijayanto, explains that the quake, although significant, was a medium-level event and does not pose an immediate tsunami threat. He discusses the risks of megathrust earthquakes in the region, emphasizing the potential for much stronger earthquakes (up to magnitude 8.9). He also highlights the importance of preparedness and public education on earthquake and tsunami risks, stressing that while the quake's impact was wide-reaching, the community’s mitigation efforts can help reduce future disaster risks.

Takeaways

• 😀 The earthquake in Pacitan, East Java, had a magnitude of 6.2, later updated to 5.8, and struck early in the morning, affecting several areas including Yogyakarta, Solo, and even Bali.
• 😀 BMKG classifies this as a 'Megatrust' earthquake due to its location in a tectonic subduction zone, which distinguishes it from typical earthquakes.
• 😀 The earthquake’s impact was felt across a wide area, including regions like Trenggalek, Yogyakarta, Solo, and even parts of Bali and West Java.
• 😀 Although the earthquake was significant, its magnitude was not high enough (6.2) to trigger a tsunami, which typically occurs with earthquakes of magnitude 7 and above.
• 😀 The most vulnerable areas to a large earthquake in the future are located along the southern coast of Java, especially in densely populated regions with soft soil.
• 😀 Areas in the southern Java coast could experience stronger shaking due to their geological characteristics, leading to potential structural damage if buildings are not earthquake-resistant.
• 😀 BMKG continuously monitors seismic activity in the region but cannot predict the exact timing of future major earthquakes, making preparedness crucial.
• 😀 Earthquake preparedness is especially important in the southern Java region, where communities need to understand how to respond to both earthquakes and potential tsunamis.
• 😀 BMKG has an early warning system in place that can inform the public within 3 minutes of detecting a significant earthquake, allowing for quicker evacuations and responses.
• 😀 BMKG is actively engaging with local communities, including schools, to educate them on what to do in case of earthquakes and tsunamis, helping to build public awareness and resilience.

Q & A

What was the magnitude and location of the earthquake discussed in the interview?

The earthquake had a magnitude of 6.2 (initially reported as 6.4) and struck the regency of in the early morning.

What type of earthquake was this event classified as?

It was a tectonic earthquake that occurred in a subduction zone, where tectonic plates meet. Although it occurred in a megathrust zone, its magnitude classified it as a moderate earthquake rather than a major megathrust event.

Why is the term "megathrust" significant in the context of southern Java?

The term "megathrust" refers to very large earthquakes that occur along subduction zones. In southern Java, megathrust earthquakes could potentially reach magnitudes above 8.0, with some estimates suggesting up to 8.9, which could cause severe damage and trigger tsunamis.

Did this particular earthquake trigger a tsunami?

No, according to , the earthquake did not trigger a tsunami because its magnitude was below the typical threshold (usually above 7.0) needed to generate significant tsunami activity in the region.

Why was the earthquake felt across a wide area?

The earthquake was relatively shallow and occurred within the subduction (intraslab) zone, allowing seismic waves to spread widely. As a result, tremors were felt across multiple regions beyond the epicenter.

Which areas are most at risk if a larger megathrust earthquake occurs in southern Java?

Coastal areas along southern Java are most at risk of tsunamis, while densely populated regions with soft soil conditions are more vulnerable to strong ground shaking and structural damage, especially if buildings are not earthquake-resistant.

Can a magnitude 6.2 earthquake trigger a larger earthquake in the region?

There is no certainty that a 6.2 magnitude earthquake will trigger a larger one. Earthquakes cannot currently be predicted precisely, and while stress interactions between faults are possible, there is no direct evidence that this event would cause a major rupture.

Is there a historical pattern of large earthquakes in southern Java?

Yes, historical records show significant earthquakes in southern Java, including events in areas such as Banyuwangi and Pangandaran. However, the recurrence intervals vary, and some segments may not have released major energy for a long time.

Why are areas with soft soil more vulnerable during earthquakes?

Soft soil can amplify seismic waves, resulting in stronger ground shaking. If buildings in these areas are not constructed to earthquake-resistant standards, the risk of structural damage increases significantly.

What mitigation measures are currently in place to address earthquake risks?

Authorities have implemented an early warning system capable of issuing alerts within approximately three minutes. Continuous public education, community preparedness programs, coordination with local disaster agencies, and school outreach initiatives are also part of ongoing mitigation efforts.

What is the key message delivered to the public regarding earthquake preparedness?

The key message is that while earthquakes cannot be predicted, preparedness and mitigation are essential. Communities should understand evacuation procedures, follow official guidance, and ensure that buildings meet earthquake-resistant standards to reduce risk.