Volcano Seismology: An Introduction
| Autor: | Vyacheslav M. Zobin |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Complexity in Tsunamis, Volcanoes, and their Hazards ISBN: 9781071617045 Encyclopedia of Complexity and Systems Science ISBN: 9783642277375 |
| DOI: | 10.1007/978-1-0716-1705-2_607 |
| Popis: | Earthquake The rupturing along the fractures and faults as well as the eruptive activity produces the seismic waves, which could vibrate the Earth surface as earthquakes. The site of initial radiation of seismic waves in the interior is earthquake focus, or hypocenter; its projection to the surface is epicenter. The seismic waves are divided into body waves and surface waves. The body waves P (compressional waves with volumetric changes) and S (shear waves without volume change) radiate from the earthquake focus; the surface Rayleigh and Love waves are formed as a result of the interaction of body waves with the surface of the Earth. The record of seismic waves is a seismogram. The earthquake size is described by magnitude M (or m), the conventional value proportional to the earthquake energy, and by seismic moment Mo. The focal mechanism characterizes the stress system acting in the earthquake source zone, while the stress drop gives the value of stress release during the earthquake. Earthquakes may form the foreshock–aftershock sequences with a main shock and the swarm sequences without any main shock. Volcano A volcano is a site at which a molten matter, known as magma and formed in the depths of the crust of the Earth, reaches the surface of the Earth from the interior. The material ejected through the vent of volcano frequently accumulates around the opening, building up a volcanic edifice. Between the main elements of a volcano, there are a volcanic cone that is the result of the accumulation of ejected material around the vent and a crater that is the surface connection of the volcanic conduit through which the ejected material reaches the surface. The crater may be situated on the summit of the cone (summit crater) or on a slope of the cone (flank crater). Beneath a volcano, we have the magma feeding system of the volcano that consists of a deep magma reservoir, or chamber which is a reservoir of magma in the shallow part of lithosphere from which volcanic material is derived; an intermediatemagma storage, a place between the magma chamber and the Earth’s surface, where magma may be collected before an eruption; and the feeding conduit, connecting the magma collectors with the surface. The surface appearance of magma is called lava. |
| Databáze: | OpenAIRE |
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