High-frequency waves following PKP-C sub diff at distances greater than 155 degree

Journal Article · Sun Apr 01 00:00:00 EST 1990 · Geophysical Research Letters (American Geophysical Union); (United States)

DOI:https://doi.org/10.1029/GL017i005p00639· OSTI ID:5315795

Nakanishi, Ichiro ^[1]

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1. Hokkaido Univ. (Japan)

Using a seismic network in Hokkaido-Tohoku region, Japan the author observes PKP waves in the distance range 152 to 157{degree} from a deep earthquake in Argentina. The seismic network consists of 26 stations and provides a data set of dense distance sampling. The examination of amplitude variation of PKP-BC and PKP-C{sub diff} with distance locates the C-cusp at about 155.5{degree} for a surface source for the path from Argentina to Japan. This C-cusp position suggests a P velocity of 10.27 km/s at the bottom of the outer core. The bandpass filtering of the data shows that high-frequency waves are observed following PKP-C{sub diff} at distances beyond the C-cusp. The waves are characterized by a dominant frequency of about 29 to 3 Hz, a long duration of oscillation until the arrival of PKP-AB, and an apparent onset slowness of about 4 s/deg, which is approximately equal to that of PKP-AB in the distance range. The onset time of the high-frequency waves seems to be consistent with the least time of the scattering of PKP-BC on the receiver side near the bottom of the upper mantle.

• OSTI ID: 5315795
• Journal Information: Geophysical Research Letters (American Geophysical Union); (United States), Vol. 17:5; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
JAPAN
SEISMIC WAVES
DATA ANALYSIS
AMPLITUDES
ARGENTINA
DEPTH
EARTH CORE
EARTH MANTLE
EARTHQUAKES
FREQUENCY DEPENDENCE
GEOLOGIC STRUCTURES
INTERFACES
SEISMIC ARRAYS
WAVE PROPAGATION
ASIA
DEVELOPED COUNTRIES
DEVELOPING COUNTRIES
DIMENSIONS
LATIN AMERICA
MEASURING INSTRUMENTS
SEISMIC EVENTS
SOUTH AMERICA
580000* - Geosciences