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The tendency of felsic lava to be cooler than mafic lava increases the viscosity difference. The silicon ion is small and highly charged, and so it has a strong tendency to coordinate with four oxygen ions, which form a tetrahedral arrangement around the much smaller silicon ion. This is called a silica tetrahedron. In a magma that is low in ...
The word lava comes from Italian and is probably derived from the Latin word labes, which means a fall or slide. [2] [3] An early use of the word in connection with extrusion of magma from below the surface is found in a short account of the 1737 eruption of Vesuvius, written by Francesco Serao, who described "a flow of fiery lava" as an analogy to the flow of water and mud down the flanks of ...
At the ocean floor, such hot supersaturated hydrothermal fluids form gigantic chimney structures called black smokers, at the point of emission into the cold seawater. Over geological time, this process of hydrothermal leaching, alteration, and/or redeposition of minerals in the country rock is an effective process of concentration that ...
Another important relationship is that if the fixed swap rate is equal to the strike of the caps and floors, then we have the following put–call parity: Cap-Floor = Swap. Caps and floors have the same implied vol too for a given strike. Imagine a cap with 20% vol and floor with 30% vol. Long cap, short floor gives a swap with no vol.
This causes enormous lava flows, accounting for 80% of Venus' surface area. Many of the mountains are large shield volcanoes that range in size from 150–400 km (95–250 mi) in diameter and 2–4 km (1.2–2.5 mi) high.
Average mortgage rates are edging down moderately week over week of Monday, January 6, 2024, though remain at elevated levels for benchmark 30-year and 15-year fixed terms, this despite three back ...
Lava coverage is proportionally smaller, about 5% since 1800, and less than 15% within the past 750 years. Zone 5 - Area on Kilauea currently protected by topography; Zone 6 - Two areas on Mauna Loa, both protected by topography; Zone 7 - Younger part of Mauna Kea volcano. 20% of this area was covered by lava in the past 10,000 years.
Andesite lava typically has a viscosity of 3.5 × 10 6 cP (3.5 × 10 3 Pa⋅s) at 1,200 °C (2,190 °F). This is slightly greater than the viscosity of smooth peanut butter. [13] As a result, andesitic volcanism is often explosive, forming tuffs and agglomerates.