At 21:22 on June 18, a 6.5-magnitude earthquake occurred in the coastal area of the western coast of Honshu, Japan (38.56 degrees north latitude, 139.52 degrees east longitude) with a focal depth of 20 kilometers. The Japan Broadcasting Association (NHK) said that a magnitude 6.8 earthquake occurred at 22:22 local time in Yamagata Prefecture, Japan, with a focal depth of 10 kilometers.
According to a news report from Tokyo, Japan (TBS) on June 18, a strong earthquake occurred in Yamaguchi Prefecture and Yamagata Prefecture in Japan. The Meteorological Agency predicts that the earthquake will produce a 1 meter high tsunami. At present, the Meteorological Agency has issued a tsunami warning to Yamagata Prefecture, Niigata Prefecture, Upper, Middle, Lower, Sado, and Ishikawa.
According to the Japan Atomic Energy Regulatory Agency, the Tokyo Electric Power Company’s Kashiwazaki-Yu-Yu nuclear power plant in Kawasaki-mura, Niigata Prefecture, Japan, and the Tohokawa Nuclear Power Plant of the Tohoku Electric Power Plant in Nagakawa-cho, Miyagi Prefecture, Miyagi Prefecture, have not found any abnormalities caused by the earthquake.According to the report, the earthquake caused about 5,900 households in Yamagata Prefecture and about 3,200 households in Niigata Prefecture to lose power.
According to global water level monitoring data, the earthquake triggered a local tsunami near the source. As of 0:10 am on June 19, 2019, the Awashima tide station (38.47°N, 139.25°E) around the source monitored a 10 cm tsunami wave and a Niigata tide station (37.94°) at 21:48. N,139.03°E) A 10 cm tsunami wave was detected at 23:06, and sag stations such as Sado, Wajima-ko and Sakata monitored a slight water shock with a volatility of no more than 10 cm.
The Japan Meteorological Agency released the first tsunami warning message at 21:24 Beijing time, and it is expected to generate a local tsunami of 20-100 cm around the source. Subsequently, the Japan Meteorological Agency released a three-phase tsunami live report, and a tsunami wave of about 10 cm was observed around the source. The Pacific Tsunami Warning Center issued a tsunami warning message at 21:43 Beijing time.
A tsunami is a destructive wave caused by a submarine earthquake, a volcanic eruption, a submarine landslide, or a meteorological change. The tsunami has a wave velocity of 700 to 800 kilometers per hour, and can cross the ocean in a few hours; the wavelength can reach hundreds of kilometers. It spreads thousands of kilometers and has little energy loss; in the vast ocean, the wave height is less than one meter, but when it reaches the shallow waters of the coast, the wavelength is shortened and the wave height is sharply increased, reaching tens of meters, forming a water wall with huge energy”.
The tsunami is mainly controlled by the seabed topography, the coastline geometry and the wave characteristics. The whistling wave ice wall repeats every few minutes or tens of minutes, destroying the embankment, inundating the land, taking away life and property, and greatly destructive.
The global tsunami-prone area is roughly consistent with the seismic zone. There are about 260 destructive tsunamis in the world, and the average is about six or seven years. The earthquake and tsunami that occurred in the Pacific Rim accounted for about 80%.The earthquakes in the Japanese archipelago and nearby seas accounted for about 60% of the Pacific earthquake and tsunami. Japan is the country with the most earthquake and tsunami in the world.