Japan withdraws erroneous magnitude-9.9 quake warning

Japan’s Meteorological Agency issued an erroneous magnitude-9.9 earthquake warning on October 16 after a quake near Russia’s Kamchatka Peninsula, then canceled the alert about eight minutes later. The agency is investigating how its warning system produced the estimate. The actual earthquake measured magnitude 6.9, according to the U.S. Geological Survey. The JMA alert forecast strong shaking across parts of northern, eastern and central Japan, including the Tokyo region. It identified the Kuril Islands area as the quake’s location, but the earthquake occurred near the Kamchatka Peninsula. The alert was issued shortly after midday in Japan and withdrawn at about 12:48 p.m. local time. It prompted emergency notifications, but the severe shaking described in the warning did not occur in Japan. Hakodate, in Hokkaido, recorded weak shaking, according to reports citing JMA data. No tsunami warning or advisory was issued. The agency apologized for the inaccurate warning and said it would explain the cause once its investigation was complete. Initial accounts attributed the error to a miscalculation in processing preliminary seismic data, but the precise technical cause has not been...