According to Sutopo, spokesperson of the Indonesian National Disaster Management Agency, the tsunami near the Sunda Strait in Indonesia was probably caused by the eruption of the Krakatoa volcano, which caused a submarine landslide.

Tsunamis are generally caused by relatively violent submarine movements, including submarine earthquakes, submarine landslides, etc. Let us use maps and animations to understand the possible causes of the tsunami in Indonesia . According to Sutopo, spokesperson of the Indonesian National Disaster Management Agency, the tsunami near the Sunda Strait in Indonesia was probably caused by the eruption of the "Krakato" volcano. Undersea landslides often occur in areas with soft geology, driving The sea surface changes violently, causing tsunamis. Waves propagate very quickly on the surface of the sea, and when they hit land at high speed, they can cause great destructive power. In addition, Sutopo also said that the high tide caused by the full moon further aggravated the power of the tsunami.

Preliminary analysis of the causes of the tsunami in the Sunda Strait of Indonesia on December 22, 2018

Banten Province near the Sunda Strait of Indonesia was hit by a tsunami on the evening of December 22, local time. So far, 222 people have been killed, 843 injured, and 28 people are missing. .

Due to the lack of actual observation data, Indonesian parties have not yet come to a definite conclusion on the cause of the tsunami. There is currently no conclusion on the cause of the Sunda Strait tsunami, but comprehensive analysis suggests that landslides caused by volcanic eruptions are most likely, and meteorological factors may objectively increase the extent of the tsunami's damage.

About Undersea volcano

Undersea volcanoes are volcanoes formed at the bottom of the ocean. Magma can be erupted from submarine craters. It is estimated that volcanoes at mid-ocean ridges alone account for 75% of the Earth's total magma. While most submarine volcanoes are found deep in the ocean, some also exist in shallow waters, and when these volcanoes erupt, they release volcanic gases into the atmosphere.

Three-quarters of the volcanic activity on Earth is submarine volcanoes. Submarine volcanoes are mainly distributed on mid-ocean ridges. The remaining volcanic activity is distributed on arcs and hot spots in the interior of the ocean, ranging in depth from more than 4,000 meters to close to the sea surface. . Observation and sampling of most submarine volcanic eruptions are carried out indirectly. If the crater is exposed above the water, the volcano can be sampled and observed by ships and satellites; if it occurs on the seabed, it can only be carried out through seabed detectors after the volcanic eruption. Conduct research on volcanoes.

Undersea volcanic composition

Undersea volcanic eruption

Undersea volcanic eruption is the most common type of volcanic eruption, but historical records and observational research are obviously insufficient. Magma overflows from submarine craters or fissures. These lava flows come into contact with water and cool rapidly. A hard crust forms on the surface of the lava, forming pillow lava. The fragments formed by the magma explosion cooled quickly and solidified to form volcanic glass and deposited. Volcanic eruptions in shallow seas can produce eruptive columns that sometimes erupt above sea level. At a depth of about 2,200 meters, the pressure exceeds the critical pressure of water (218 atmospheres), and the seawater no longer boils. It becomes a supercritical fluid . There is no boiling sound, so it is difficult to detect. to deep-sea volcanic eruptions.

The deepest submarine volcano eruption photographed in May 2009 (Source: "Scientists Discover and Image Explosive Deep-Ocean Volcano". NOAA. 2009-12-17.)

Pillow lava produced by Hawaiian submarine volcano (Source: Wikipedia )

There are two types of eruptions of submarine volcanoes: one is the slow overflow of magma to form large lava bubbles that burst and erupt; the other is an explosion caused by the rapid rise of volcanic gas. Lava and volcanic gases have different effects on climate and ecosystems, so it's important to be able to distinguish between these types of eruptions.

Krakatoa eruption photos

How undersea volcanic eruptions cause tsunamis

Tsunamis are huge, destructive waves, most of which are formed by undersea earthquakes. They can also come from the eruption of an undersea volcano or the collapse of an island. Huge landslides are formed. These landslides are often caused by earthquakes or volcanic eruptions. When fast-moving landslides enter the water or move rapidly underwater, tsunamis are generated. (From: Volcano Research Center of China Earthquake Administration)