Mount Fuji spray fire to 252?Academician Liu Jiaqi: Impossible

Text ｜ "China Science News" reporter Feng Lifei

Mount Fuji in Japan is about to eruption? Recently, this guess has swept the Internet.

According to the recent reports of the Japanese Times, the Japanese Police Department has begun to make comprehensive preparations for Mount Fuji to eruption and distribute the dust -proof mask to the local police department.

It is reported that if Mount Fuji erupted, the volcanic ash may affect the Tokyo Metropolitan circle, and all departments should make corresponding preparations as soon as possible.

In addition, the number of fire -spray ports has increased by about 5 times, and "threatening" such as the local earthquake, etc., seems to "sit down" the rumors of Mount Fuji who are about to eruption.

Is this the case? The "China Science News" interviewed Liu Jiaqi, a volcanic research expert and a member of the Chinese Academy of Sciences.

The online transmission "is about to eruption" lacks scientific support

"China Science News": The spitting outlet of Mount Fuji has increased from 44 excitements 17 years ago to 252, an increase of about 5 times; at the beginning of this year, Mount Fuji has reached 1.6 MPa, which has met the eruption conditions. In addition, there have been four and fifth earthquakes near Mount Fuji last year. Does these "precursors" indicate that the magma under Mount Fuji has been "ready to go"?

Liu Jiaqi: First of all, the crater changed from 44 to 252, and this data must be wrong.

How can there be so many volcanic mouths? Unless the entire area is volcano.

For example, the Hawaii volcano is widely distributed and there will be many crater.

Mount Fuji is an overall volcano, with an area of ​​about 1,200 square kilometers, much smaller than Changbai Mountain. If a volcano has more than 200 crater, it is "full of holes."

The most recorded eruption of Mount Fuji was from December 16, 1707 to January 1, 1708, and it has been more than 300 years. It has left three volcanic mouths -a main volcanic mouth on the top of the mountain and two volcanic mouths on the mountainside of the mountainside. Essence

Secondly, the so -called surface cracks and underground pressure are not necessary for volcanic eruption. The volcano is really closely related to the earthquake. An important means to predict volcanic eruption are earthquakes. Frequent earthquakes are an important symbol of volcanic activity. It can be used to speculate the status of volcanic activity. It will definitely erupt.

"China Science News": What conditions do volcanic eruptions do? Is Mount Fuji the most dangerous volcano in Japan?

Liu Jiaqi: There are three basic conditions for volcanic eruption.

First of all, there must be magma (library) underground, which is the material foundation of volcanic eruption. Otherwise, the crustal activity will not be erupted again; second, there must be magma channels (volcano), such as broken, cracks, etc.; Enough motivation to spray magma from underground to the surface, such as sectors dive, structural activities, etc.

On these conditions, it is also necessary to determine the specific location, time, scale, type, strength (level) of the volcanic eruption. These are closely related to the scale, the nature of the magma, and the depth of the burial. And how to eruption.

So volcanic monitoring and forecasting is a very complicated and difficult system work.

There are dozens of active volcanoes in Japan, including more dangerous volcanoes than Mount Fuji. Japan has been monitoring Mount Fuji or other volcanoes for a long time, and work is very detailed. I have not seen the professional inference of Mount Fuji to eruption, and cannot be erupted by rumors.

History eruption "The explosive power is not very strong"

"China Science News": Is the scale of Mount Fuji in history large?

Liu Jiaqi: As the highest peak in Japan, Mount Fuji accumulated after many eruptions to form the current height.

Mount Fuji has a record of about 18 times, and the earliest eruption was more than 80,000 years ago.

In the past 10,000 years, there are three main records: Bao Yongda eruption in 1707, the eruption of Zhenguan in 864, and the extension eruption in 802.

In 1707, the eruption was mainly based on base magma. There were more magma flowing out, but the explosive power was not very strong.

Male magma is a complex silicate substance. According to the content of silicon oxide, it can be divided into base, neutral, acidic, and hyper acidicity.

Batobular magma fluidity is relatively large, but the explosive power is not very strong; acidic magma has great viscosity and poor liquidity, but the explosive power is relatively strong.

"China Science News": At present, it has been more than 300 years since the last eruption of Mount Fuji. The magma has accumulated for so long. Will there be a large -scale destruction after eruption?

Liu Jiaqi: First of all, Mount Fuji is very important in Japan. It is surrounded by big cities in Japan and the most developed regions. It is less than 100 kilometers from Tokyo to the east. In the west, there are ancient houses, Kyoto, Osaka, Nara and other cities. kilometer.

Once Mount Fuji erupted, it will have a great impact on the surroundings. The volcanic ash will reach Tokyo in less than two hours. It is normal for cities such as Nagoya. They are basically within the scope of volcanic eruption.

But it is not possible to judge how much impact on Mount Fuji.

To answer this question, you need to find out four aspects: when can volcanic eruptions, how large the scale is eruption, what is the type of eruption, and how many volcanic ash will be.

In addition, the weather and wind direction of volcanic eruption must be considered.

The type of volcanic eruption is different, and the harm is different.

The scale of the eruption of Hawaii is not small, but it is often erupted, causing losses and harm is not great; but the harm of violent volcanic eruption in Indonesia and the Philippines is completely different. Scientific prevention should be based on the scientific judgment of eruption and scale, and minimize the impact of disaster.

Japan's volcanic eruption monitoring prediction level is internationally ahead, and has the ability to make more accurate forecasts.

"China Science News": Which of the magma and volcanic ash during volcanic eruption is more harmful?

Liu Jiaqi: It depends on the specific environment around the volcano. According to the specific analysis of different situations, sometimes the magma will destroy the surrounding buildings or vegetation, and sometimes the volcanic ash will bury the surrounding space to pollute the surrounding environment.

Toxic gases such as hydrogen sulfide and carbon monoxide sprayed from volcanic must also consider its impact.

It is also necessary to consider potential secondary disasters. For example, in 1985, the debris caused by the outbreak of Colombia's volcanic volcanic outbreaks, except for 70 or eighty kilometers, destroyed a small town, causing more than 20,000 people to die.

Be wary of disasters should also protect natural gifts

"China Science Journal": What impact can Mount Fuji have on China?

Liu Jiaqi: It will definitely have a certain impact, but Mount Fuji is more than 1,000 kilometers from Beijing, just like the eruption of the Tanga volcano at the beginning of the year.

It is good for everyone to care about natural phenomena such as volcanoes, but it should not exaggerate its impact. Too much hype will lose science.

"China Science Journal": In the era of urbanization, how should people take a plan for such disasters such as volcanic eruption?

Liu Jiaqi: The urban circle has developed into the volcanic area, and there must be danger.

But many people don't care about these things.

For example, the eruption of the Vesuway volcano near the Naples in Italy destroyed the ancient city of Pompeii in 79 AD, but now there are still many people living there; Very close to the volcanic mouth.

There are basically no volcanoes around the major cities in mainland China, so there is basically no impact in this regard; however, if the Datun volcanic group in Taiwan in my country will be erupted in the future, it will definitely bring danger to cities around Taipei and other cities and other cities such as Taipei and be vigilant.

"China Science News": In 2013, Mount Fuji was selected into the World Cultural Heritage. What do you think of further volcanic eruption may have the impact of its cultural value?

Liu Jiaqi: No more eruption may destroy all existing landscapes, and may even create new landscapes, so it will not have much impact on its value.

In fact, the current landscape of Mount Fuji was formed after many eruptions. For example, it was only 2,900 meters high at 864 AD, and now it has reached 3775.63 meters, which is the result of the continuous pile of volcanic lava.

As a natural phenomenon and natural product, its eruption will cause greater harm. It should avoid or reduce disasters as much as possible, but it can also create wealth that is far greater than harm to human beings, such as Fuji Mountain in Japan, American Yellowstone Park, China Changbai Mountain, these well -known landscape tourism areas are volcanic areas.

We should cherish the valuable natural heritage of "Great Sculptor", a "great sculptor", awe and protect them.

"China Science News" (2022-06-27 The 1st edition of the news)

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