Temporal gravity variations associated with the November 1975 deflation of Kilauea Volcano

Conference · Wed Dec 01 04:00:00 EST 1976 · EOS, Trans., Am. Geophys. Union; (United States)

OSTI ID:5414693

Jachens, R ^[1]; Eaton, G; Lipman, P; Okamura, R

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1. Geological Survey, Menlo Park, CA

Repeated high-precision gravity measurements made near the summit of Kilauea Volcano, Hawaii have revealed temporal variations in gravity associated with the deflation of the volcano that followed the earthquake and eruption of November 29, 1975. Gravity differences with respect to a base station located on the south flank of Mauna Loa were measured at 18 sites within 5 km of Kilauea Crater. The original survey, conducted between November 10 and November 23, 1975, was repeated during the two weeks following the earthquake. Standard errors of the gravity differences measured during both surveys average about 5 ..mu..gal. These two surveys indicate that gravity at sites near the summit of Kilauea increased with respect to gravity at sites located away from the summit. The pattern of gravity increase is roughly radially symmetrical about the geodetically determined locus of this deflation event, located approximately 1 km southeast of Kilauea Crater, and has a half-width of 2.2 km. The gravity changes correlate closely with elevation changes that occurred between level surveys conducted on September 22, 1975 and January 8, 1976. The relation between gravity change and elevation change (-1.70 +- 0.07 (s.e.) ..mu..gal/cm)) determined from these data shows that the local mass distribution beneath the summit of Kilauea changed during the time between the surveys. Mass balance calculations indicate that the volume of subsidence is too small to account for the gravity changes, presumably because some magma moved away from the summit area without complete collapse of the resulting voids.

• OSTI ID: 5414693
• Conference Information: Journal Name: EOS, Trans., Am. Geophys. Union; (United States) Journal Volume: 57:12
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150301* -- Geothermal Exploration & Exploration Technology-- Geophysical Techniques & Surveys
GEOPHYSICAL SURVEYS
GRAVITY SURVEYS
GROUND SUBSIDENCE
HAWAII
IGNEOUS ROCKS
KILAUEA VOLCANO
MAGMA
NORTH AMERICA
ROCKS
USA
VARIATIONS
VOLCANOES