Mega Earthquake: Japanese authorities have issued a warning that a ‘great earthquake’ could hit Japan’s northern coast within the next week. An earthquake of 7.5 magnitude occurred in this area on Monday. The Japan Meteorological Agency (JMA) said the earthquake that struck late Monday night has increased the possibility of another earthquake of similar or greater intensity in the region. The epicenter of this earthquake, which occurred at 11:15 pm, was at a depth of 54 kilometers off the Pacific coast of Aomori. Japan’s ‘great earthquake’ warning means the risk of an earthquake of magnitude eight or greater off its North Pacific coast is higher than normal, but it will not happen because the probability is very low.
What is the meaning of this warning?
A magnitude 7.5 earthquake struck at a depth of about 54 kilometers off the Pacific coast of Aomori in northern Honshu on Monday night. Due to which small tsunami waves of about 60 to 70 cm height arose and at least 30-33 people were injured. While about 90,000 residents were forced to move to safer places. The tremors were so strong that roads cracked, some buildings were damaged and were felt as far as Tokyo, about 550 kilometers to the south.
Risk of major earthquake is about 1%
Under rules to be implemented in 2022, the Japan Meteorological Agency (JMA) issues a ‘great earthquake warning’ when an earthquake of magnitude seven or greater occurs in or near the known source areas of giant earthquakes located along the Japan and Kuril (Chishima) Trench. This is the first warning for the Hokkaido-Sanriku region, stating that the risk of an earthquake of magnitude eight or greater next week is ‘relatively higher than normal’, but officials estimate the risk to be about one percent.
What is a great earthquake?
A mega earthquake is an extremely powerful earthquake, whose intensity is measured at 8.0 or more on the Richter scale. Such earthquakes occur very rarely, but they are devastating and can cause devastation on a large scale. Such as bursting of the ground, collapse of buildings and creating huge tsunami waves. A great earthquake can bring a tsunami up to 30 meters high. Due to this, about two lakh people may die, several lakhs of basic structures may be destroyed and there may be an economic loss of 31 trillion yen. Such a great earthquake can cause not only seismic tremors but also additional disasters like tsunami, landslides and hypothermia in winter. Many people can be affected by this.
Difference between great earthquake and earthquake
This difference lies in the intensity, impact area and destructive capacity of a great earthquake and a normal earthquake. The intensity of a normal earthquake is less than 8.0 on the Richter scale, while a mega earthquake is of intensity 8.0 or more, which causes prolonged tremors over a large area. Normal earthquakes are limited to local level and cause moderate damage. But great earthquakes are caused by large-scale movement of plates on major fault lines, causing disasters like ground ruptures, landslides and huge tsunamis.
Why are scientists worried?
Japan lies above a major subduction zone where the Pacific Plate subducts beneath the North American and Okhotsk plates along the Japan and Kuril Trench. This accumulates enormous stress which sometimes results in megathrust earthquakes. In 2011, a magnitude 9.0 earthquake struck Tohoku near the Japan Trench, triggering a devastating tsunami that killed about 20,000 people and damaged the Fukushima Daiichi nuclear plant. The concern now is that Monday’s magnitude 7.5 event could either be a sharp pre-quake or a part of a broader pressure adjustment in the same trench system. Officials are using this advisory to encourage households and local governments to refresh evacuation plans, secure supplies and be prepared to take immediate action if a strong earthquake or major tsunami warning is issued.
warning is nothing new
Warning of ‘great earthquake’ is nothing new. Japan issued its first alert for a major earthquake originating from a nearby oceanic trench called the Nankai Trench, after a 7.1-magnitude earthquake struck the south of the country in August 2024. There were no related earthquakes and citizens were able to return to their daily lives a week later. But despite Japan’s frequent exposure to such tremors, its location on the Pacific Ocean’s ‘Ring of Fire’ means that earthquakes, both felt and non-feelable, occur approximately every three minutes.
