What is an earthquake zone? For countries located in the earthquake zone, is a strong earthquake really a fate that cannot be avoided?
The area where the crust plates are squeezed and collided is a zone with strong seismic activity, called a seismic zone. From the outline, most seismic zones are located in the junction of plates and are generally considered to be places where strong earthquakes may occur in the future. In terms of space, there are three major seismic zones in the world, namely the Pacific Rim Seismic Zone, the Eurasian Seismic Zone (Mediterranean - Himalayan Seismic Zone ) and the Hailing Seismic Zone.
▲Distribution map of the world seismic belt
The Pacific Rim seismic belt is distributed around the Pacific Ocean, like a huge garland, separating the continent from the ocean, and surrounding the Pacific Ocean on the edges of the adjacent continents and islands. This earthquake zone concentrates 80% of the earth's earthquakes, including a large number of shallow-source earthquakes, 90% of the middle-source earthquakes, almost all deep-source earthquakes and most of the world's super-large earthquakes.
The Pacific Rim seismic belt starts from the Andes on the west coast of South America, passes through the southern end of South America, Mexico , and the west coast of North America to the Japanese archipelago, and then divides into two branches, one goes southeast through Mariana Islands , Guam to Yap Islands ; the other goes southwest through Ryukyu Islands , Taiwan, and the Philippines, and converges with the Mediterranean-Indonesia seismic belt, and goes southeast through the Solomon Islands to New Zealand .
Because the Pacific plate moves the fastest, it suddenly subducts directly from the trench into the heart of the earth, causing the plate to deform and continuously trigger earthquakes. Therefore, the earthquakes in the Pacific Rim seismic zone are the most and strongest, and now the Pacific plate has added new variables.
Looking back at history, countless earthquakes have occurred in the Pacific Rim seismic belt...
What about Japan?
I believe most people think that Japan is the country with the most earthquakes in the world, and to a more accurate statement, China, like Japan, is the country with the most severe earthquake disaster in the world.
Our neighbor, Japan, is located west of the Pacific Rim. It is like sitting on a shaking chair. There are more than 1,000 earthquakes occur every year. Since the 20th century, more than 50 earthquakes of hrs 66 or above... The magnitude 9.0 earthquake that occurred in Japan on March 11, 2011 is the strongest earthquake measured in the world so far. Therefore, Japan deserves to be the title of "volcanic earthquake country".
Tips: The Japanese archipelago is located on the Eurasian and North American plates belonging to the land plate, while the Pacific and Philippine plates belonging to the marine plate will subdue below these two plates. It will move from time to time, allowing the Japanese to withstand earthquake disasters while always guarding against tsunamis.
, the west coast of the United States, is located on the east side of the Pacific Rim volcanic seismic belt. In the western part of California, from Los Angeles to San Francisco to Pacific Ocean, a San Andres fault has developed with a total length of more than 965 kilometers. It is a world-famous active fault. Most of the strong earthquakes in the United States occur here. Since the 20th century, 14 earthquakes of magnitude 6 or above occurred on the west coast of the United States, including the magnitude 8.6 earthquake in San Francisco on April 18, 1960 shocked the world.
The Eurasian seismic belt (Mediterranean-Himalayan seismic belt) is from the Mediterranean to the east. One branch passes through Central Asia to the Himalayas, then goes south through my country's Hengduan Mountains, passes Myanmar, and turns east in an arc shape to Indonesia . The other branch extends from Central Asia to the northeast and reaches Kamchatka, and is distributed relatively scattered.
The earthquake in the Eurasian earthquake zone is caused by the continuous movement of the African, Arab and Indian plates to the north and colliding with the Eurasian plates. The Eurasian earthquake zone concentrates 15% of the earth's earthquakes, mainly shallow-source earthquakes and middle-source earthquakes, and lacks deep-source earthquakes.
ridge earthquake zone is an earthquake zone in the ocean. It starts from the northern shore of Siberia near the estuary of the Lena River, passes through the Arctic through the Spitsbergen Islands and Iceland , and then passes through the central Atlantic ridge to some narrow ridge zones or seabed uplifts of Indian Ocean , and has a branch that penetrates the Red Sea and the famous East Africa Rift Valley.
So what about China? It is difficult to achieve both worlds. While China has a vast territory, it is also suffering from earthquake disasters brought to the Chinese people by this land. Unfortunately, China is located between the two most active seismic zones in the world, and some areas are even part of these two seismic zones.
my country is at the intersection of two major seismic belts, namely the Pacific Rim Seismic Belt and the Eurasian Seismic Belt (Mediterranean-Himalayan Seismic Belt). Some areas are part of these two seismic Belts. Taiwan Province of our country is located in the Pacific Rim earthquake zone. The Eurasian earthquake belt runs from west to east, and the western part of China, including Xinjiang, Tibet, Qinghai, Sichuan and Yunnan, are just at the end of the Eurasian earthquake belt. Affected by them, my country's earthquake activities are not only frequent and intense, but also have a wide range of earthquake activities, and over-stable earthquakes have occurred in almost all provinces across the country. For example, Wenchuan, Sichuan is located in the Eurasian earthquake zone. In fact, the reason why the Wenchuan earthquake caused huge casualties is that this earthquake was a shallow source earthquake with the source less than 10 kilometers from the ground. According to statistics, mainland earthquakes in my country account for about one-third of the world's continental earthquakes, with an average of 30 earthquakes of magnitude 5 or above every year; since the last century, my country has occupied about 35% of the strong earthquakes of magnitude 7 or above on the continent, making it a country with multiple earthquakes.
▲Section structure map of China and surrounding areas
Source: Institute of Geology of China Earthquake Bureau
From 2004 to the present, humans have experienced Indonesian earthquake , China Wenchuan earthquake , Chile earthquake , Haiti earthquake , China Taiwan earthquake , Mexico earthquake, China Qinghai Yushu earthquake, Japan earthquake, etc. Compared with the data from the previous 20 years, we can find that the two lions, the Pacific Rim earthquake belt and the Eurasian earthquake belt, have been obviously awakened.
If we count all earthquakes above magnitude 4 in the Pacific Rim seismic zone from 2009 to the present, we will be surprised to find that many earthquakes above magnitude 7 have occurred here. It can be seen that the energy accumulated in the Pacific Rim seismic zone is very powerful, far beyond human imagination. The Eurasian earthquake zone also continuously releases huge energy through the Wenchuan earthquake in China, the Yushu earthquake in Qinghai, the Afghanistan earthquake, and the Turkish earthquake.
