Japanese Prime Minister Fumio Kishida has decided to cancel his scheduled trip to Central Asia in order to lead the government's response following a warning by scientists of a possible "megaquake" off the country's southern coast. The move comes as the Japan Meteorological Agency issued its first-ever "megaquake advisory," raising concerns about a potential major earthquake triggered by the underwater Nankai Trough.

The alarm was sounded after a magnitude 7.1 earthquake struck just off the eastern coast of Kyushu island on Thursday. Although the tremor resulted in no significant damage, it prompted seismologists at the agency to convene an emergency meeting to assess the risk of a major quake and its potential impact on the nearby Nankai Trough. As a precautionary measure, they urged the public to exercise heightened caution for the next week.

Prime Minister Kishida, acknowledging the gravity of the situation, announced the cancellation of his Aug. 9-12 trip to Kazakhstan, Uzbekistan, and Mongolia. The focus now shifts to ensuring that the government's emergency measures and communication channels are fully operational in response to the potential seismic threat.

In light of the "megaquake advisory," the Fire and Disaster Management Agency has directed 707 municipalities identified as being at risk from a Nankai Trough earthquake to review their disaster response strategies and evacuation plans. This proactive approach aims to mitigate the potential impact of a major quake should it occur.

The issuance of the "megaquake advisory" has caused public unease, leading local government offices, rail operators, and various agencies to implement precautionary measures. While this has affected travelers during the summer "Obon" holiday week, officials and experts stress that normal activities should continue. The advisory simply serves as an awareness-raising measure, highlighting the increased probability of a major quake in the long term, without specifying a timeframe or location.

Chief Cabinet Secretary Yoshimasa Hayashi has encouraged people to carry on with their daily social and economic activities, including traveling. However, some municipalities, such as Higashi Osaka, have advised residents to avoid unnecessary and non-urgent travel in case a major quake occurs. Other measures taken by local governments include opening shelters, urging residents to stock up on emergency supplies, and facilitating discussions on evacuation plans within families.

In response to the advisory, the popular seaside town of Shirahama in Wakayama prefecture announced the closure of its four beaches, outdoor hot springs, parks, and other facilities for the next week. Additionally, an annual fireworks festival scheduled for Saturday has been canceled. Aoshima, another beach resort in Miyazaki prefecture, which was most affected by Thursday's quake, has also been closed.

Trains serving the region will be operating at slightly reduced speeds as a precautionary measure. Rail companies are taking necessary precautions to ensure the safety of their passengers amidst the heightened concerns.

In a 2013 report, a government disaster prevention team expressed that if a magnitude 9.1 earthquake were to strike near the southern coast, it could generate a devastating tsunami exceeding 10 meters (33 feet), potentially resulting in a death toll of more than 300,000 and economic damage exceeding 220 trillion yen ($1.5 trillion) in a worst-case scenario.

As Japan remains on high alert, the government continues to prioritize the safety and well-being of its citizens, implementing necessary measures to address the potential threat of a "megaquake" and minimize its impact.