Search results
Results from the WOW.Com Content Network
Tephra is a generalized word for the various bits of debris launched out of a volcano during an eruption, regardless of their size. [4] Pyroclastic materials are generally categorized according to size: dust measures at <1/8 mm, ash is 1/8–2 mm, cinders are 2–64 mm, and bombs and blocks are both >64 mm. [5] Different hazards are associated with the different kinds of pyroclastic materials.
A wide variety of volcanic processes can produce tsunamis. This includes volcanic earthquakes, caldera collapse, explosive submarine eruptions, the effects of pyroclastic flows and lahars on water, base surges with accompanying shock waves, lava avalanching into the sea, air waves from explosive subaerial eruptions, avalanches of cold rock, and avalanches of hot material. [1]
Debris avalanche deposit of Tata Sabaya in Bolivia Cross-section diagram showing (a) pre-collapse volcano, (b) after collapse, (c) new edifice built on top of collapsed old edifice. At volcanoes, the term landslide is commonly used for slope movements with shear and displacement in a relatively narrow zone. [7]
It’s possible for volcanoes to have a short-term impact on the climate – including global temperature cooling – due to the gases they inject high into the upper atmosphere.
These characteristics make sulphur dioxide a good target for volcanic gas monitoring. It can be detected by satellite-based instruments, which allow for global monitoring, and by ground-based instruments such as DOAS. DOAS arrays are placed near some well-monitored volcanoes and used to estimate the flux of SO 2 emitted.
Mauna Loa, a shield volcano in Hawaii An Ancient Greek warrior's shield—its circular shape and gently sloping surface, with a central raised area, is a shape shared by many shield volcanoes. A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground.
The Waw an Namus volcano is surrounded by an apron of dark tephra, which has a notable color contrast to the surrounding Sahara Desert. Africa's volcanoes have had an impact on the fossil record. Geographically a part of Africa, El Hierro is a shield volcano and the youngest and smallest of the Canary Islands.
On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example, a mid-ocean ridge , such as the Mid-Atlantic Ridge , has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has ...