scholarly journals Earthquake relocations, fault zone geometry and constraints on lateral velocity variations using the joint hypocenter determination method in the Taiwan area

2005 ◽  
Vol 57 (9) ◽  
pp. 809-823 ◽  
Author(s):  
Kwang-Hee Kim ◽  
Jer-Ming Chiu ◽  
Jose Pujol ◽  
Kou-Cheng Chen
Keyword(s):  
Fault Zone ◽  
Determination Method ◽  
Lateral Velocity ◽  
Hypocenter Determination ◽  
Joint Hypocenter Determination ◽  
Velocity Variations ◽  
Taiwan Area

Seismicity and tectonics of western Venezuela

1972 ◽  
Vol 62 (6) ◽  
pp. 1711-1751 ◽  
Author(s):  
James W. Dewey
Keyword(s):  
Fault Zone ◽  
South American ◽  
Seismic Zone ◽  
South American Plate ◽  
Intermediate Depth ◽  
Hypocenter Determination ◽  
Joint Hypocenter Determination ◽  
Shallow Earthquakes ◽  
Seismicity And Tectonics ◽  
North And South

abstract New seismicity data on western Venezuela and northeastern Colombia are presented. Teleseismically recorded earthquakes from 1930 through 1970 have been relocated by Joint Hypocenter Determination (JHD) or with source-station adjustments calculated by JHD. Additionally, 540 days of recording have been obtained with local seismographs installed near the Boconó Fault. The most intense shallow activity occurred north and south of the Tachira Depression along the eastern flank of the Cordillera Oriental of Colombia. The Boconó Fault Zone is seismically active; small shallow shocks were recorded in it by the local stations. Shallow earthquakes also occur in the Cordillera de Mérida away from the Boconó Fault. The new hypocenters for the intermediate-depth Bucaramanga earthquakes define a smaller source volume than defined by previously computed hypocenters. A previously inferred southward-dipping seismic zone near Bucaramanga is probably spurious, a consequence of correlation between errors in latitude and errors in depth. If one assumes that these intermediate-depth earthquakes lie on a single lithospheric slab, that slab strikes approximately north and dips to the east. The distribution of hypocenters and focal mechanisms support the platetectonic hypothesis that the present tectonics of northwestern Venezuela are a result of eastward motion of the Caribbean plate with respect to the South American plate. The principal interface between these two plates may have changed within the last 5 m.y. from a zone of underthrusting west of the Sierra de Perija to the predominantly right-lateral Boconó Fault Zone.

Interpretation of seismic reflection profiling data for the structure of the San Andreas fault zone

1983 ◽  
Vol 73 (6A) ◽  
pp. 1701-1720
Author(s):  
R. Feng ◽  
T. V. McEvilly
Keyword(s):  
Fault Zone ◽  
Seismic Reflection ◽  
San Andreas Fault ◽  
Velocity Model ◽  
Seismic Reflection Profile ◽  
Lateral Velocity ◽  
Zone Structure ◽  
Ray Method ◽  
Velocity Change ◽  
San Andreas

Abstract A seismic reflection profile crossing the San Andreas fault zone in central California was conducted in 1978. Results are complicated by the extreme lateral heterogeneity and low velocities in the fault zone. Other evidence for severe lateral velocity change across the fault zone lies in hypocenter bias and nodal plane distortion for earthquakes on the fault. Conventional interpretation and processing methods for reflection data are hard-pressed in this situation. Using the inverse ray method of May and Covey (1981), with an initial model derived from a variety of data and the impedance contrasts inferred from the preserved amplitude stacked section, an iterative inversion process yields a velocity model which, while clearly nonunique, is consistent with the various lines of evidence on the fault zone structure.

Monitoring of crustal seismic velocity variations in the L'Aquila fault zone inferred from noise cross-correlation

2015 ◽  
Vol 202 (1) ◽  
pp. 604-611 ◽  
Author(s):  
Gaia Soldati ◽  
Lucia Zaccarelli ◽  
Licia Faenza ◽  
Alberto Michelini
Keyword(s):  
Fault Zone ◽  
Cross Correlation ◽  
Seismic Velocity ◽  
Velocity Variations ◽  
Noise Cross Correlation

Including Lateral Velocity Variations Into True-Amplitude Wave-Equation Migration

2009 ◽  
Author(s):  
D. Amazonas ◽  
R. Aleixo ◽  
J. Schleicher ◽  
J. Costa ◽  
A. Novais ◽  
...  
Keyword(s):  
Wave Equation ◽  
Lateral Velocity ◽  
Amplitude Wave ◽  
Velocity Variations

The Interpretation of Seismic Reflection Data from the Western Platform Region of Taranaki Basin

1988 ◽  
Vol 6 (2) ◽  
pp. 136-150 ◽  
Author(s):  
Glenn P. Thrasher
Keyword(s):  
Travel Time ◽  
Seismic Reflection ◽  
Time Data ◽  
Lateral Velocity ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Travel Time Data ◽  
Velocity Variations ◽  
Thickness Variations ◽  
Reflection Characteristics

The western-most region of Taranaki Basin, the Western Platform, has a stratigraphy which permits subdivision into major seismic units. The reflectors separating these units are easily identifiable. Each of the units and reflectors has typical reflection characteristics which are often correlatable with the lithology of the unit. Lateral velocity variations, caused by lateral deposition and compaction variations in prograding sequences, area major problem in developing depth conversion models for this region. Analysis of travel time data from wells shows that velocity variations in both the Oligocene-Miocene and Pliocene-Pleistocene sequences are predictable from the thickness variations of the units (and hence from interval travel times). The imerval velocity variations of the Paleocene-Eocene transgressive sequence are dependent on the overburden history and lithology of the unit.

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