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Long‐term infrared surveillance of Lascar Volcano: Contrasting activity cycles and cooling pyroclastics
Author(s) -
Wooster Martin J.
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl011904
Subject(s) - pyroclastic rock , volcano , impact crater , radiance , geology , phreatic eruption , peléan eruption , vulcanian eruption , infrared , thermal infrared , phreatomagmatic eruption , explosive eruption , seismology , magma , remote sensing , astronomy , physics
Lascar Volcano (Chile) erupted on 20 July 2000, generating a >10 km high ash column. Satellite infrared data have previously indicated that Lascar's large vulcanian explosions are preceded by significant cooling within the active crater, suggesting that characteristic thermal radiance trends can act as remotely detectable eruption precursors. New analyses and data extend the Lascar's thermal history to cover all five large vulcanian eruptions occurring over the last 15 years. The 2000 eruption follows a formerly undocumented style of infrared radiance variation and indicates that Lascar may have modified its activity since 1993, the year of its greatest historical eruption. Therefore such patterns, evident for over a decade at Lascar, can be unexpectedly modified and this has implications for the way apparent thermal precursors should be treated. The largest 1993 eruption produced 8.5 km long pyroclastic flows which the infrared data indicate exhibited exponential cooling over an 8–12 months period.