Home World News Southern California scholars say Hualien earthquake caused geological disasters: landslides and surface liquefaction

Southern California scholars say Hualien earthquake caused geological disasters: landslides and surface liquefaction

Southern California scholars say Hualien earthquake caused geological disasters: landslides and surface liquefaction

Hualien, TaiwanEarthquakeThis attracted the attention of people in Southern California.University of Southern California(USC) seismologist Professor Li Yonggang said local people need to pay attention to more serious secondary geological disasters that may occur in the Hualien area, such as landslides and liquefaction.

Li Yonggang said that the United States Geological Survey revealed that a major earthquake measuring 7.4 on the Richter scale occurred off the east coast of Taiwan on the 3rd. The epicenter of the earthquake was located about 18 kilometers south of Hualien city. The earthquake was felt throughout the island. The depth of this M7.4 strong earthquake was 34.8 kilometers, and the maximum ground shaking intensity in the epicenter area was MMI=8.5-9 degrees. The focal mechanism is reverse-thrust faulting, which is the result of the collision of the Pacific Plate, the Philippine Plate, and the Eurasian Plate. Due to the large proportion of the oceanic plate, it moves westward and subducts itself beneath the continental plate off the island of Taiwan. Subduction zones form along plate boundaries. The upper part of the intruding oceanic plate (slab) is called the Benioff Zone, where large amounts of strain energy are stored. This earthquake of 7.4 magnitude occurred in the subduction zone Benioff Zone.

Houses in Hualien County, Taiwan are leaning, according to preliminary damage reports. Due to the aftershocks (one magnitude 6.4, three magnitude 5.7, and four magnitude 5.2 aftershocks), the military has been deployed for disaster relief, and schools and workplaces have suspended operations. Taiwan’s Central Weather Bureau issued a tsunami warning after the earthquake and advised residents to move to higher ground.JapanThe meteorological agency issued a tsunami warning for Miyako Island and the Okinawa Islands, warning that wave heights could reach 3 meters.

He said the 7.4-magnitude earthquake was the most powerful earthquake to hit Taiwan in 25 years. Taiwan is located in the Pacific Rim Seismic Belt. In 1999, a magnitude 7.7 earthquake struck Chizi, 150 kilometers south of Taipei, killing 2,400 and injuring 10,000. In 2018, a magnitude 6.2 earthquake struck near Hualien, killing at least 17 people and injuring more than 300. 9 people died and 963 were injured in the earthquake in Taiwan. After the main shock, 13 aftershocks of magnitude 5 or greater occurred, with the largest having a magnitude of 6.4. 26 buildings collapsed in the Hualien area, and landslides damaged the coastal highway. Casualties are still being searched and rescued, and traffic is being repaired. Fortunately, the epicenter of this powerful 7.4 magnitude earthquake was located in an area with sparse residential density along the coast of Taitung, so damage was relatively minimal.

The intensity of the strong earthquake that struck south of Hualien off the coast of Taitung was calculated based on teleseismic amplitude and phase data recorded by 46 broadband seismic stations in different directions by the Global Seismic Network, and satellite deformation measurement data. Was combined with. The moment MO released by the Hualien earthquake was 1.42 x E20 Newton metres, which is equivalent to an earthquake of magnitude 7.37 on the Richter scale. Of course, this calculation is the result of a rapid earthquake report (completed by a supercomputer within 3 hours of the main earthquake). The final determination of earthquake intensity can also be based on local short-range seismic networks at the epicenter of the earthquake (such as the dense network deployed by the Central Weather Bureau of Taiwan on the island of Taiwan), specifically recorded local ground vibration intensity MMI data. Strong earthquakes have been detected by accelerometer stations. The final intensity of a strong earthquake.

The central mechanism of the Hualien earthquake is reverse-thrust faulting. (Provided by Li Yonggang)

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