Crustal and uppermost mantle S-wave velocity below the East European Craton in northern Poland from the inversion of ambient-noise records

Shear-wave seismic data recorded along four profiles during the SNoRE 97 (1997 Slave Northern Cordillera Refraction Experiment) refraction wide-angle reflection experiment in northwestern Canada are analyzed to provide S-wave velocity (Vs) models. These are combined with previous P-wave velocity (Vp) models to produce cross sections of the ratio Vp/Vs for the crust and upper mantle. The Vp/Vs values are related to rock types through comparisons with published laboratory data. The Slave craton has low Vp/Vs values of 1.681.72, indicating a predominantly silicic crustal composition. Higher values (1.78) for the Great Bear and eastern Hottah domains of the Wopmay orogen imply a more mafic than average crustal composition. In the western Hottah and Fort Simpson arc, values of Vp/Vs drop to ∼1.69. These low values continue westward for 700 km into the Foreland and Omineca belts of the Cordillera, providing support for the interpretation from coincident seismic reflection studies that much of the crust from east of the Cordilleran deformation front to the Stikinia terrane of the Intermontane Belt consists of quartzose metasedimentary rocks. Stikinia shows values of 1.781.73, consistent with its derivation as a volcanic arc terrane. Upper mantle velocity and ratio values beneath the Slave craton indicate an ultramafic peridotitic composition. In the Wopmay orogen, the presence of low Vp/Vs ratios beneath the Hottah Fort Simpson transition indicates the presence of pyroxenite in the upper mantle. Across the northern Cordillera, low Vp values and a moderate-to-high ratio in the uppermost mantle are consistent with the region's high heat flow and the possible presence of partial melt.

Download Full-text

Investigating Near Surface S-Wave Velocity Properties Using Ambient Noise in Southwestern Taiwan

Terrestrial Atmospheric and Oceanic Sciences ◽

10.3319/tao.2014.12.02.05(eosi) ◽

2015 ◽

Vol 26 (2-2) ◽

pp. 205 ◽

Cited By ~ 6

Author(s):

Chun-Hsiang Kuo ◽

Kuo-Liang Wen ◽

Che-Min Lin ◽

Strong Wen ◽

Jyun-Yan Huang

Keyword(s):

Wave Velocity ◽

Ambient Noise ◽

S Wave ◽

Near Surface ◽

Southwestern Taiwan

Download Full-text

Nodal Seismograph Recordings of the 2019 Ridgecrest Earthquake Sequence

Seismological Research Letters ◽

10.1785/0220200203 ◽

2020 ◽

Vol 91 (6) ◽

pp. 3622-3633

Author(s):

Rufus D. Catchings ◽

Mark R. Goldman ◽

Jamison H. Steidl ◽

Joanne H. Chan ◽

Amir A. Allam ◽

...

Keyword(s):

Wave Velocity ◽

Large Volume ◽

Ambient Noise ◽

Temporal Variations ◽

Earthquake Sequence ◽

S Wave ◽

Data Set ◽

Fault Structure ◽

Nodal Data ◽

Dense Arrays

Abstract The 2019 Ridgecrest, California, earthquake sequence included Mw 6.4 and 7.1 earthquakes that occurred on successive days beginning on 4 July 2019. These two largest earthquakes of the sequence occurred on orthogonal faults that ruptured the Earth’s surface. To better evaluate the 3D subsurface fault structure, (P- and S-wave) velocity, 3D and temporal variations in seismicity, and other important aspects of the earthquake sequence, we recorded aftershocks and ambient noise using up to 461 three-component nodal seismographs for about two months, beginning about one day after the Mw 7.1 mainshock. The ∼30,000Mw≥1 earthquakes that were recorded on the dense arrays provide an unusually large volume of data with which to evaluate the earthquake sequence. This report describes the recording arrays and is intended to provide metadata for researchers interested in evaluating various aspects of the 2019 Ridgecrest earthquake sequence using the nodal data set.

Download Full-text

The crust and uppermost mantle s-wave velocity structure beneath japan islands revealed by joint analysis of p-and s-wave receiver functions

Malaysian Journal of Geosciences ◽

10.26480/mjg.02.2017.20.23 ◽

2017 ◽

Vol 1 (2) ◽

pp. 20-23 ◽

Cited By ~ 9

Author(s):

Jun Wang ◽

Hongtai xu

Keyword(s):

Wave Velocity ◽

Velocity Structure ◽

Receiver Functions ◽

Joint Analysis ◽

S Wave ◽

Uppermost Mantle

Download Full-text

Upper crustal velocity structure of Pearl River Delta, China, derived from dense-array observations of ambient noise

10.5194/egusphere-egu2020-7811 ◽

2020 ◽

Author(s):

Zuoyong Lyu ◽

Xiuwei Ye ◽

Jinshui Lyu ◽

Xiang Zhang ◽

Liwei Wang ◽

...

Keyword(s):

Wave Velocity ◽

Pearl River Delta ◽

Ambient Noise ◽

River Delta ◽

Tectonic Activity ◽

Pearl River ◽

Inversion Method ◽

S Wave ◽

The Pearl River ◽

Velocity Zone

<p>The Pearl River Delta, located in the middle of the southeast coast of south China, is a graben basin. Although this region is considered tectonically relatively inactive, many small earthquakes still occur, and multi groups of faults with different directions are well developed. To better understand the geological structures in this region, we use about 30 days of ambient noise data from 88 portable stations and 38 permanent broadband stations to obtain a high-resolution 3D upper crustal S-wave velocity model. Over 3700 Inter-station group-velocity curves were measured in the 1-10 s period range and tomographically inverted by a direct surface wave inversion method in a 0.05&#176;&#215;0.05&#176;grid. The checkerboard test shows that the tomographic final resolution is 0.1&#176;&#215;0.1&#176;. Our results show that in the shallow crust of the study area, the velocity distribution corresponds to surface geology and geological features. The Huizhou-Dongguan depression and the Pearl River mouth exhibit low S-wave velocity feature, while the high S-wave velocity zone corresponds to the distribution of Mesozoic granite. Some faults are almost between low velocity and high velocity zone, which may play an important role of the channel of magmatic activity. The upper crustal structure in this area is closely related to the intense magmatic tectonic activity and crustal extension since Mesozoic.</p>

Download Full-text