Characteristics of seismic waves composing Hawaiian volcanic tremor and gas-piston events observed by a near-source array

Journal Article · Wed Apr 10 00:00:00 EDT 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JB02781· OSTI ID:5387671

Ferrazzini, V; Aki, K ^[1]; Chouet, B ^[2]

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1. Univ. of Southern California, Los Angeles (USA)
2. Geological Survey, Menlo Park, California (USA)

A correlation method, specifically designed for describing the characteristics of a complex wave field, is applied to volcanic tremor and gas-piston events recorded by a semicircular array of GEOS instruments set at the foot of the Puu Oo crater on the east rift of Kilauea volcano, Hawaii. The spatial patterns of correlation coefficients obtained as functions of frequency for the three components of motion over the entire array are similar for gas-piston events and tremor, and clearly depict dispersive waves propagating across the array from the direction of Puu Oo. The wave fields are composed of comparable amounts of Rayleigh and Love waves propagating with similar and extremely slow phase velocities ranging from 700 m/s at 2 Hz to 300 m/s at 8 Hz. The results from Puu Oo stand in sharp contrast to those obtained in an experiment conducted in 1976 on the partially solidified lava lake of Kilauea Iki. Rayleigh waves were not observed in Kilauea Iki, but well-developed trains of Love waves were seen to propagate there with velocities twice as high as those observed near Puu Oo. These differences in the propagation characteristics of surface waves at the two sites may be attributed to the presence of a soft horizontal layer of molten rock in Kilauea Iki, which may have lowered the phase velocity of Rayleigh waves more drastically than that of Love waves, resulting in severe scattering of the Rayleigh wave mode. On the other hand, the thin superficial pahoehoe flow under the array at Puu Oo may have favored the development of vertical columnar joints more extensively at this location than at Kilauea Iki, which may have reduced the shear moduli controlling Love wave mode.

• OSTI ID: 5387671
• Journal Information: Journal of Geophysical Research; (United States), Vol. 96:B4; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
HAWAII
VOLCANOES
SEISMIC WAVES
ASHES
CORRELATIONS
FREQUENCY DEPENDENCE
GEOLOGIC STRATA
GROUND MOTION
LAVA
LOVE WAVES
RAYLEIGH WAVES
SEISMIC ARRAYS
SOLIDIFICATION
VELOCITY
VOLCANIC GASES
WAVE PROPAGATION
COMBUSTION PRODUCTS
DEVELOPED COUNTRIES
FEDERAL REGION IX
FLUIDS
GASES
GEOLOGIC STRUCTURES
MEASURING INSTRUMENTS
MOTION
NORTH AMERICA
PHASE TRANSFORMATIONS
RESIDUES
SEISMIC SURFACE WAVES
USA
580000* - Geosciences