Strong seismic scatterers near the core-mantle boundary west of Mexico

被引：44

作者：

Niu, FL

Wen, LX

机构：

[1] Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA

[2] SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA

来源：

GEOPHYSICAL RESEARCH LETTERS | 2001年 / 28卷 / 18期

关键词：

D O I：

10.1029/2001GL013270

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

PKP phases observed in Japan show strong precursors with clear onsets for earthquakes that occurred in south America. The onset times of the PKP precursors can all be explained by existence of seismic scatterers in the lowermost 100 km. of the mantle west of Mexico, within an area of 200 km x 300 km. Forward modeling of PKP precursor amplitudes indicates that a P-wave velocity variation of at least 6% is required to explain the large amplitudes of the observed PKP precursors, suggesting that the core-mantle boundary region beneath west of Mexico is a highly anomalous region characterized by strong seismic scatterers.

引用

页码：3557 / 3560

页数：4

共 14 条

[1] SEISMIC WAVE SCATTERING NEAR CORE-MANTLE BOUNDARY - NEW INTERPRETATION OF PRECURSORS TO PKP [J].

CLEARY, JR ;

HADDON, RAW .

NATURE, 1972, 240 (5383) :549-&

[2]

Doornbos D. J., 1972, Physics of the Earth and Planetary Interiors, V5, P387, DOI 10.1016/0031-9201(72)90110-0

[3]

Haddon R. A. W., 1974, Physics of the Earth and Planetary Interiors, V8, P211, DOI 10.1016/0031-9201(74)90088-0

[4] An analysis of large-scale variations in small-scale mantle heterogeneity using Global Seismographic Network recordings of precursors to PKP [J].

Hedlin, MAH ;

Shearer, PM .

JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 2000, 105 (B6) :13655-13673

[5] Seismic evidence for small-scale heterogeneity throughout the Earth's mantle [J].

Hedlin, MAH ;

Shearer, PM ;

Earle, PS .

NATURE, 1997, 387 (6629) :145-150

[6]

HIRAHARA K, 1993, J GEOMAGN GEOELECTR, V45, P1265

[7] PRECURSORS TO PKIKP AND SEISMIC-WAVE SCATTERING NEAR MANTLE-CORE BOUNDARY [J].

HUSEBYE, ES ;

KING, DW ;

HADDON, RAW .

JOURNAL OF GEOPHYSICAL RESEARCH, 1976, 81 (11) :1870-1882

[8] TRAVELTIMES FOR GLOBAL EARTHQUAKE LOCATION AND PHASE IDENTIFICATION [J].

KENNETT, BLN ;

ENGDAHL, ER .

GEOPHYSICAL JOURNAL INTERNATIONAL, 1991, 105 (02) :429-465

[9] Seismic evidence of partial melt within a possibly ubiquitous low-velocity layer at the base of the mantle [J].

Revenaugh, J ;

Meyer, R .

SCIENCE, 1997, 277 (5326) :670-673

[10] Evidence for partial melt at the core-mantle boundary north Tonga from the strong scattering of seismic waves [J].

Vidale, JE ;

Hedlin, MAH .

NATURE, 1998, 391 (6668) :682-685

← 1 2 →