The Geospatial Information Agency (BIG) and a number of agencies discovered the existence of an undersea mountain, about 260 kilometers south of Pacitan Regency, East Java. Volcanoes are spread all over the Earth, from the surface to the bottom of the sea.
From Hawaii to Indonesia to Iceland, hundreds of islands around the world have been formed by underwater volcanoes. Underwater volcanoes, exactly as the name suggests, are volcanoes that are located below sea level.
Because they erupt into water instead of air, underwater volcanoes behave very differently from terrestrial volcanoes. For example, undersea volcanoes rarely experience explosive eruptions.
The weight of the water above it, creates enormous pressure, usually producing what is known as a passive lava flow along the ocean floor. Most of the eruptions do not disturb the sea level.
Charles Mandeville, program coordinator for the Volcano Hazards Program of the United States Geological Survey (USGS) monitors 169 active volcanoes, all of which are terrestrial in the United States. Prior to joining the USGS, Mandeville focused his research on underwater volcanology becoming an expert on Indonesia's famous 1883 eruption of the island of Krakatau.
According to Mandeville, there are two main factors that contribute to underwater volcanoes and eventually form islands, namely magma supply and tectonic activity.
"The first thing you need is a supply of magma. Usually, in most oceanic island volcanoes or underwater volcanoes, you need to melt the Earth's mantle," he said, quoted from National Geographic.
Most volcanic islands originate from passive lava flows on the ocean floor. This passive flow hardens into rock and builds up an underwater mountain range over millions of years. Finally, some volcanoes reach heights above the ocean floor where lower pressure allows explosive eruptions to occur. Underwater volcanoes that do not reach sea level are called seamounts.
"In addition to the magma supply, plate tectonics plays a major role in determining which undersea volcanoes will eventually form islands. Tectonic activity can sometimes take island volcanoes from mantle-derived sources of magma, as the tectonic plates on which those volcanoes grow are growing. move," Mandeville said.
Volcanic Island Ecosystem
Formed only from rocks, volcanic islands have very vibrant ecosystems. This ecosystem developed over millions of years, together with the island. Life on volcanic islands begins with the most basic building blocks, namely autotrophic bacteria.
"There are bacteria that can make their food only from chemical elements and part of the elements emitted from volcanoes. Once they have an established microscopic ecosystem, they have an adequate food supply to support larger life," says Mandeville.
Species from nearby landscapes also contribute to ecosystem development. Passing birds may stop to nest on new islands, bringing seeds and spores from the mainland or other islands. Living plants can float in the ocean until they end on the edge of the island.
Because they evolved in such an isolated environment, many organisms are considered endemic species. Described by the 19th century naturalist Charles Darwin, the finches, which are endemic to the Galapagos Islands, are one famous example. This bird is found only in the isolated Galapagos Islands.