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The combination of large amounts of volcanic ash emitted by volcanic eruptions and heavy rainfall can form mudslides that can wash away roads and bridges, flood nearby villages and cities, and make countless people homeless. Mud formed from soil and rock debris can flood entire cities.

Volcanic eruptions are a natural phenomenon. The reason is that molten material from the Earth's interior is ejected under pre ssure. The types of volcanoes include active volcanoes, extinct volcanoes and dormant volcanoes. The only way to control volcanic activity is through early pre vention.

Extended information:

1. Formation principle

The temperature and density inside the earth are uneven. Formation of mantle convection currents or mantle plumes. When hot material rises to the shallow parts of the Earth, partial melting occurs due to reduced pre ssure.

Under the influence of external forces, these molten materials come together and form magma pockets in the shallow parts of the Earth. When the pre ssure in the magma sac is greater than the pre ssure in the formation, magma will break through the crust along faults or weak points, causing volcanic eruptions.

Another volcano is caused by the interaction of plates. For example, in the subduction zone or collision zone of plates, local high temperatures are formed due to friction, and the dehydration of some water-containing minerals also lowers the melting point of the rock. At this time Magma pockets can also form, triggering volcanic activity.

2. Eruption Process

1. Magma Formation and Initial Rise Stage

The generation of magma must involve two processes: partial melting and melting and parent rock separation. In fact, it is unlikely that these two processes are independent of each other, and the separation of the melt from the parent rock may occur when melting begins.

Partial melting is the coexistence state of liquid (i.e. magma) and solid (crystalline). Partial melting can occur when temperature increases, pre ssure decreases and the solidus line decreases. When part of the molten material rises with the mantle flow, the separation of liquid and solid will also occur during the flow, resulting in liquid movement and even aggregation, which is called melting.

2. Magma sac stage

A magma sac is an area filled with magma under a volcano. It is a place where magma is relatively enriched in the rock medium of the earth's crust or upper mantle. Generally regarded as high-temperature fluids in rock pores (or fissures) similar to oil reservoirs, it is generally believed that within the mantle plume, magma only accounts for 5%-30% of the total volume.

From a local perspective, it can be regarded as a liquid collection with relatively internal circulation. Magma is a mixture of molten magma, volatiles, and crystals.

3. From the magma sac to the surface stage

The rise of the path of magma from the magma source area to the near surface is related to the excess pre ssure of the magma sac, the formation and penetration of the channel, and It is related to the crystallization and degassing processes of magma as it rises.

When the tensile or tensile-shear stress in the crust is greater than the local rock fracture strength, tensile or tensile-shear fractures may form. If these cracks are connected to each other, they can serve as the basis for magma eruption. aisle. Huge lightning often appears during eruptions.

Reference source: Baidu Encyclopedia - Volcano Eruption

Reference source: Baidu Encyclopedia - Volcano

The current weather in Yunnan is not very good, and heavy rains have occurred in some cities, causing certain impacts. When traveling recently, please be aware that roads in these areas of Kunming are filled with water. If you want to drive out, you should try to avoid them.


The Yunnan Meteorological Observatory issued a yellow warning for strong convection


The Yunnan Meteorological Observatory continued to issue a yellow warning for strong convection at 16:30 on July 28: It is expected that the next 12 Hours, thunder and lightning, short-term heavy pre cipitation, local strong winds, Severe convective weather such as hail.


National Defense Guidelines


1. The government and relevant departments shall make pre parations for short-term protection against heavy rains, lightning protection, and strong winds in accordance with their responsibilities. The meteorological department shall Make good pre parations for artificial hail pre vention;


2. Outdoor pedestrians and staff should reduce outdoor activities and stay away from scaffolding, billboards and other structures;


3. Drive poultry and livestock to a place with a roof, close the doors and windows and reinforce the shed;


4. Check the drainage system of cities, farmland, and fish ponds, and do a good job in drainage and pre vention of flash floods, landslides, mudslides and other disasters pre paration.


The latest weather news in Kunming


From the day of the 28th to the day of the 29th, due to the influence of convergent shear, the city will be cloudy with moderate rain, accompanied by heavy rain in some areas Strong convective weather such as thunderstorms and strong winds, short-term heavy rainfall, strong winds, and hail. The cumulative rainfall is expected to reach 30 to 50 mm.


Currently, Kunming is in the main flood season. Compared with the same period in history, pre cipitation is slightly higher than normal.


Specific weather forecast for the main urban area of ​​Kunming


July 29, cloudy with moderate rain, 17~24;

< br/>On July 30, it will be cloudy with moderate rain, from 17 to 25;


On July 31, it will be cloudy with showers, from 17 to 25.


The latest announcement on the Jishui section of Kunming


As of 17:30 on the 28th:


First of all, two Flooded water points were cut off.


1 Panlong District: Beijing Road Changlong Building Materials Market (newly added).


Wuhua District 1: The intersection of Tongyuan North Road and Yuanxi Road.


Second, vehicle traffic is slow at 13 flooded water points.


Guandu District 2: Gudukou Road, South Ring Road, under the bridge, East Second Ring Road, under the Jinma Overpass.


Building 7 in Xishan: Chunyuan Community section of Yunshan Road, the intersection of Renmin West Road and Haiyuan Middle Road, the intersection of Haigang Road and Qianwei West Road, the intersection of Huachang Road and Yongchang Road, Daguan Road It is at the intersection of Huancheng West Road, Laoshian Highway and Chejiabi Railway Bridge, and under the Mingbo Overpass of the West Second Ring Road.


Four in Wuhua District: North Second Ring Road Macun Interchange, Xichang Road Dayun Hospital, Xichang Road (Daguan Road to Wacang West Road), Jiaoling Road, Kehua Road.


A landslide near a café on Wenlin Street


According to a report from the @Wuhua District Huashan Street Office, Kafka Café on Linwen Street A landslide occurred nearby, and flood control teams went to the scene to deal with it. Please pay attention to the safety of passers-by and avoid other roads.


Please call the 24-hour flood control hotline of Huashan Street at 0871-65362323.