Japan’s recent earthquake, which struck southern Japan on Thursday with a magnitude of 7.1, didn’t cause significant damage, and the tsunami warning was quickly lifted. However, it was followed by an unusual warning from Japan’s meteorological agency about an increased risk of a “major earthquake.” This unprecedented alert led Japan’s Prime Minister to cancel a planned trip to Central Asia to stay in the country for the week.
Many Japanese people are now thinking about the “big one,” a once-in-a-century quake long warned about. Worst-case scenarios predict it could cause over 300,000 deaths and a tsunami up to 30 meters (100 feet) high along Japan’s Pacific coast. Despite the alarming predictions, Masayo Oshio from Yokohama expressed confusion and uncertainty, saying, “I am baffled by the advisory and don’t know what to make of it.”
Why Are Japanese Authorities Concerned?
Japan experiences about 1,500 earthquakes a year due to its location on the Ring of Fire. Most are minor, but significant quakes like the 2011 magnitude 9.0 earthquake, which caused a devastating tsunami and over 18,000 deaths, do occur.
Authorities are worried about a possible “megathrust” earthquake along the Nankai Trough, a seismic zone along Japan’s Pacific coast. Historical records show that such quakes occur roughly every hundred years. The last major ones were in 1944 and 1946. Experts estimate there’s a 70% to 80% chance of a magnitude 8 or 9 quake in the next 30 years, which could be catastrophic, causing massive damage and many casualties.
Can Earthquakes Be Predicted?
According to Robert Geller, a seismology professor at the University of Tokyo, predicting earthquakes isn’t scientifically reliable. He explained that while earthquakes can occur in clusters, it’s impossible to know if a quake is a foreshock or an aftershock. Only about 5% of earthquakes are foreshocks. The 2011 earthquake was preceded by a foreshock that was largely ignored.
The Japan Meteorological Agency (JMA) used its new warning system for the first time on Thursday. While it advised people to prepare, it didn’t mandate evacuations, aiming to avoid causing undue panic. Prime Minister Fumio Kishida canceled his trip to ensure proper preparation and communication. Some, like Masayo Oshio, feel the government might be overreacting, while others, including Prof. Geller, view the advisory as not particularly useful.
How Are People and Authorities Responding?
The alert has prompted many to review their emergency preparedness. In Nichinan, Miyazaki Prefecture, officials checked evacuation shelters. In Kochi Prefecture, at least 75 shelters were opened, and Jera Co., a thermal plant operator, activated its emergency protocols. Kuroshio and Wakayama Prefectures also urged voluntary evacuations and confirmed evacuation routes.
Despite skepticism from experts, Prof. Geller suggests it’s a good reminder to ensure routine preparedness. “Have a week’s worth of water, some canned food, and batteries for your flashlight,” he advises.