The Secret of Wenchuan Earthquake (12 Wenchuan Earthquake Passed 13)

A 4.8-magnitude earthquake occurred in Wenchuan, Sichuan: chandeliers in residents' homes shook.

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According to the China Seismological Network, the China Seismological Network officially determined that an earthquake of magnitude 4.8 occurred at 23: 36 on July 14 in Wenchuan County, Aba Prefecture, Sichuan Province (30.97 degrees north latitude and 103.37 degrees east longitude) with a focal depth of 15 km.

Image from @ China Seismological Network

After the earthquake, many netizens said that the earthquakes in Chengdu, Deyang and Leshan were obvious.

The chandeliers in Chengdu residents' homes are obviously shaking.

The picture comes from CCTV news.

Image from Weibo screenshot

An earthquake of magnitude 4.8 occurred in Wenchuan late at night.

The earthquakes in Chengdu, Deyang and Leshan are obvious.

/kloc-On the evening of July, 0/4, an earthquake of magnitude 4.8 occurred in Wenchuan. The earthquake caused a strong earthquake in Dujiangyan, especially in Chengdu, Deyang and Leshan. Towns and towns within 20km of the epicenter are sanjiang town, Xuankou, Gengda, Yingxiu and Wolong. The epicenter was 26 kilometers from Dujiangyan, 48 kilometers from chongzhou city and 76 kilometers from Chengdu.

Image from @ China Seismological Network

The chandeliers in Chengdu residents' homes are obviously shaking.

The picture comes from CCTV news.

After the earthquake, China Earthquake Warning Network generated earthquake warning information 5 seconds after the earthquake, and Chengdu received the warning information 19 seconds before the earthquake wave arrived.

The Wenchuan earthquake in Chengdu received an early warning 19 seconds in advance.

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What happened after the Wenchuan earthquake?

What is the local situation after Wenchuan earthquake? According to an on-site person in Shuimo Town, Wenchuan, it was thundering and raining. Affected by the earthquake, some residents took refuge in the square of Shuimo Town from their homes. However, some residents are still eating barbecue calmly and are not affected at all. According to Wenchuan Fire, at present, there are no reports of casualties in this earthquake.

Image from Sichuan Online

According to CCTV news reports, as of 7: 00 am on July 15, the rainfall in Wenchuan County has stopped. According to the disaster reports of towns and villages, there are no reports of casualties and disappearances, and there are no reports of major property losses and infrastructure damage in the county.

Wenchuan has persuaded 538 tourists to return.

Placement 157 tourists

According to Sichuan observation news, as of 9: 00 on June 5438+05, Wenchuan County has taken the initiative to avoid risks, transferred and resettled 36 people 1 1 household, persuaded 538 tourists to return, and properly resettled tourists 157. Two geological disasters were reported, with no casualties. At present, Wenchuan County has organized two professional teams, together with local counties, townships, village cadres and monitoring personnel, to investigate the hidden dangers of secondary disasters in Yingxiu area of Xuankou and Mian area of Weizhou.

In terms of transportation, after the Wenchuan "7.14" earthquake with magnitude 4.8, the relevant departments have carried out investigations on the damage of transportation infrastructure. As of 8: 30 on July 15, after investigation, the Mawen Expressway, Du Wen Expressway and Chengguan Expressway near the earthquake zone were all in normal traffic, and the toll station of Pudu Expressway (West Third Wheel) was temporarily closed due to heavy rain. At present, the main roads leading to towns and villages in Wenchuan County remain unblocked.

"5 12" Wenchuan earthquake has passed 13 years.

Why are there aftershocks?

According to the introduction of Sichuan Seismological Bureau, the June 14 Wenchuan M 4.8 earthquake is located in the southern section of Wenchuan aftershock area, which belongs to an undulating activity in Wenchuan aftershock area.

It is reported that since 1970, earthquakes of magnitude 4.0 and above 120 (including Wenchuan aftershock) have occurred within 50 kilometers of the epicenter of this earthquake of magnitude 4.8. Among them, there were 4.0-4.9 earthquakes 100, 5.0-5.9 earthquakes 15, 6.0-6.9 earthquakes 4 times and 8.0 earthquakes 1 time. Among these earthquakes, the most recent one was the earthquake of magnitude 4.0 in Wenchuan County, Aba Prefecture, Sichuan Province on February 26th, 20th17th, and the earthquake of magnitude 8.0 in Wenchuan County, Sichuan Province on May 2nd, 2008 was the largest with the closest spatial distance.

The "512" Wenchuan earthquake occurred in 2008, and it has been 13 years. Why are there aftershocks in Wenchuan? In this regard, Sun Shizhen, a researcher at China Seismological Network Center, said that the so-called aftershocks were artificially defined. It is generally believed that the energy release after an earthquake needs a process, and earthquakes will continue to occur during the release process, thus forming an earthquake sequence. The largest earthquake in this series is called the main earthquake, followed by aftershocks and preceded by foreshocks. Take "5. 12" Wenchuan earthquake in 2008 as an example, it was a main earthquake and aftershock earthquake. There was no foreshock in front, and a series of aftershocks occurred behind. Aftershocks decay slowly, sometimes for more than ten years or even longer. Of course, sometimes it will be short, and it will end in a few days.

Sun Shizhen: How can we be sure that this is an aftershock? For example, can the earthquake with magnitude 4.8 in Wenchuan in July of 14 be called the aftershock of the "5 12" earthquake? This needs to be judged according to the whole earthquake sequence, that is, to divide the whole earthquake sequence since the "5. 12" Wenchuan earthquake. If the earthquake is continuous, then this earthquake can now be called an aftershock. If there is no earthquake in the middle, it is not appropriate to call the earthquake that happened after that "aftershock".