Lava flow is liquid on the surfaceflowOfLavaThe solid rock accumulation formed by the cooling of lava flow is sometimes called lava flow.The temperature of lava flowing in liquid state lava flow is usually between 900 ° C and 1200 ° C. If there is more gas in lava, it can flow at lower temperature.Acidic lava is viscous and flows not far away. Large area lava flows are often basic lava.When the temperature is high and the slope is steep, the flow velocity of lava flow can reach 65km per hour.The shape of lava flow depends on many aspects, such as lava composition（basalt、Andesite、Dacite、Rhyolite）、flow、terrainAnd environment, etc.[1]
Lava flowing on the ground in liquid form.Its temperature is usually between 900 ℃ and 1200 ℃. If there is more gas in the lava, even lower temperatures can flow.Acid lavaSticky, not far flowing, even blocked in the crater;Basic lava has strong mobility. When the lava source is sufficient and the terrain is suitable, it will spread widely and far.[2]
Formation and characteristics
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Lava flowing along the earth's surface as liquid from the crater and fissure.The apparent slope andMagmaThe degree of lava flow varies. Some lava flows are long and narrow belts, and some are broad and gentle tongues (see figure).The temperature of newly ejected lava rarely exceeds the melting point, which is between 900 ℃ and 1200 ℃ according to its composition and gas volume.When the gas content in lava is high, it can flow before cooling to 700 ℃.The basic lava has low viscosity and high fluidity. The flow rate depends on the slope, up to 45~65 km/h, generally 15 km/h.The acid lava is viscous, flows not far, and even chokes in the crater.When the lava cools and condenses, or the gas is exhausted and becomes foamy, its viscosity increases and its movement slows down.The solidified lava forms a special shape on the surface, most commonly on landRope lavaandMassive lava, and in waterPillow lavaEtc.[3]
Lava flow refers to the lava flowing from the crater, which is formed in non explosive eruption or explosive eruption lavafountain。Where lava flows go, they are completely destroyed, but in most cases, people have a certain time to stay away from them because of their slow flow rate.
Flow rate determinants
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The speed of lava flow depends on the following points:
Japan's administrative independent legal person marine research and development institution is located in the eastthe pacific oceanThe largest seafloor lava has been found on the seafloor, which is located at 14 degrees south latitude and 112 degrees west longitude, with an area of 340 square kilometers.
The lava discovered this time not only rewrites the record of submarine lava flow, but also discovers the classicalPlate tectonic theoryUndocumented East Pacific submarine uplift, the most active plate forming uplift on the earthvolcanic activity。Such a large-scale lava flow is an important factor to change the surface environment of the earth, and has received great attention from scientists.From the analysis of the scale and shape of lava flow, it may be that huge heat and volcanoes erupted in the ocean in a short period of about 10 yearsGasCaused by.
2022On October 31, the world's first 1:2.5 million lunar rock type distribution map led by Shandong University was released.This figureIncluding 5 types of lunar sea basalt (including 923 lava flow units in total)[4]。
