Continuous monitoring with in situ sensors
The previous chapter described several ways to measure volcano deformation by making repeated network surveys. Frequent surveys of a well-designed network can serve to characterize the deformation field in space and time, albeit not completely nor continuously, thereby helping to constrain source models and anticipate future activity. However, this approach has two serious shortcomings during a crisis: (1) it repeatedly places survey personnel near a hazardous volcano, potentially in harm’s way; and (2) repeated surveys cannot always keep pace with a rapidly evolving crisis, especially at night or during bad weather. Therefore, it is desirable to supplement periodic geodetic surveys with carefully sited continuous sensors that provide a steady stream of data in real time for analysis.
KeywordsGlobal Position System Volumetric Strain Proof Mass Volcanic Explosivity Index Absolute Gravimeter
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- 14.Relative relocation algorithms take advantage of the fact that errors in absolute hypocenter locations are largely attributable to sources, such as an imperfect seismic-velocity model, that affect tightly clustered events more or less equally (i.e., the errors are common-mode). The effect of common-mode errors can be reduced to the extent that hypocentral errors shrink by one to two orders of magnitude, revealing such structures as active fault planes and magma pathways (e.g., Prejean etal., 2002).Google Scholar