Seismic and source characteristics of large chemical explosions. Final report

Abstract

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Craters and Granular Jets Generated by Underground Cavity Collapse

“…Nevertheless, there are alternative processes, such as volcanic eruptions and explosions, that can also produce craters [5][6][7][8][9][10][11][12]. For instance, a maar is a natural depression created by an underground steam explosion that occurs when magma comes into contact with shallow groundwater [7].…”

“…Similarly, gas trapped within a viscous silica-rich magma chamber can explode forming craters called calderas (these structures have been also observed in extraterrestrial surfaces) [12]. Likewise, subsidence craters can be artificially produced in nuclear tests [9][10][11] and, undesirably, in oil drilling operations [13].…”

“…In nuclear tests, it would be hard to find a constant α due to the difficulties of achieving reproducible soil conditions [9][10][11]27]. In order to determine the crater shape, a flat sheet covering half of the crater was illuminated from above; the shadow was projected vertically over the surface revealing its profile [see the example in Fig.…”