Research Warns of Potential Mega-Quake Risk in Chishima Trench, Hokkaido
A study warns that unreleased stress energy in the Chishima Trench off Hokkaido may trigger a mega-quake of magnitude 9. The research indicates increased strain between tectonic plates and a historical precedent for significant seismic activity in the region. Experts urge for awareness and preparedness in light of this potential threat.
Researchers from Tohoku and Hokkaido universities, along with the Japan Agency for Marine-Earth Science and Technology, have released findings indicating that the unreleased stress energy in the Chishima Trench off Hokkaido could potentially lead to a magnitude 9 mega-quake. This conclusion stems from a five-year study of seismic activity in the region.
Historically, a significant earthquake is believed to have occurred in this area in the 17th century. The government’s earthquake panel has assessed that there is a 7 to 40 percent probability of a quake measuring at least 8.8 happening within the next 30 years.
To gather data, the research team installed GPS observation stations on the seabed in 2019, focusing on the point where the oceanic plate subducts beneath the continental plate. They found that both the ocean and continental plate stations shifted about 8 centimeters per year towards one another, indicating that the plates are strongly coupled and strain is accumulating over time.
Assuming that the plates have remained in this joined state since the last major quake, the researchers estimate that the accumulated strain could equate to the energy released by a mega-quake. Plans are underway to extend studies to additional sites off Hokkaido.
Tomita Fumiaki, an assistant professor at Tohoku University’s International Research Institute of Disaster Science, emphasized the importance of remaining vigilant about the risk of future mega-quakes, noting that public memory of the devastating 2011 Great East Japan Earthquake and Tsunami is waning. He encourages readiness for potential seismic events.
The findings indicate significant seismic risks associated with the Chishima Trench, emphasizing the need for awareness and preparedness due to high potential for a mega-quake. Historical data alongside current strain assessments portray a concerning scenario. Continuous monitoring and studies are essential to better understand and mitigate risks in the region.
Original Source: www3.nhk.or.jp
