Japan’s Earthquake Risks: How Likely Is a Megaquake?

On August 8, 2024, a 7.1 magnitude earthquake struck near the city of Miyazaki on Japan's Kyushu Island. This event has raised concerns about the potential for a larger, more destructive earthquake in the future.

Japan’s history of seismic activity in the Nankai Trough subduction zone indicates that earthquakes with magnitudes between 8 and 9 occur every 100 to 200 years. However, the recent 7.1 magnitude shock happened in an area prone to smaller, repeating earthquakes, making the likelihood of triggering a megaquake uncertain.

Experts, including Shinji Toda from Tōhoku University and Ross S. Stein and Volkan Sevilgen from Temblor, Inc., suggest that while this region has experienced significant seismic activity, the specific characteristics of the recent quake might not be enough to bring the megathrust fault closer to a catastrophic rupture.

Following the 7.1 event, Japan's Meteorological Agency issued a 'Megaquake Advisory' due to the increased probability of a large quake. While the advisory is a cautionary measure, the scientific community remains divided on the actual risk of an imminent megaquake.

Historic records and recent seismic activity in the Nankai Trough suggest that the region may continue to experience moderate to strong earthquakes. Still, the absence of megathrust events within 100 kilometers of the recent quake's epicenter could imply that a megaquake is not imminent.

Given Japan’s preparedness and advanced warning systems, authorities and residents are urged to stay informed and ready, but the evidence points to a lower likelihood of a megaquake resulting from this recent seismic activity.

Essential Insight:

• The 7.1 magnitude earthquake in August 2024 has sparked concerns about a larger quake.
• Historically, the Nankai Trough has produced significant seismic events, but this recent shock may not trigger a megaquake.
• Japan's government has issued a 'Megaquake Advisory' as a precaution, but the scientific consensus on the likelihood of a major event remains mixed.

For more detailed analysis, visit the original article by Toda, Stein, and Sevilgen on Temblor's website: Japan’s magnitude 7.1 shock triggers megaquake warning.