An Analysis on Deep Crustal Structure Along the Onshore‐Offshore Seismic Profile Across the Binghai (Littoral) Fault Zone in Ne South China Sea

Zhao, Mengmeng; Qiu, Xin; Ye, CM; Xia, KY; Huang, CL; Xie, JB; Wang, P

doi:10.1002/cjg2.573

Cited by 32 publications

(19 citation statements)

References 9 publications

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“…In August of 2001, South China Sea Institute of Oceanology, Taiwan Ocean University and Earthquake Administration of Guangdong Province (EAGP) worked together and completed an onshore-offshore seismic profile offshore Shantou City in northeastern SCS(P-2001) [20][21][22] . This profile is more than 500 km long which starts from Xintang(X) Town, Raoping County and Nan'ao Island(N) of Guangdong Province, extends southwards and crosses land-sea transitional zone(A), continental shelf(B), and continental slope, and reaches the abyssal basin(C).…”

Section: Characteristics Of Crustal Structure In Epicentral Area and mentioning

confidence: 99%

Characteristics of the crustal structure and hypocentral tectonics in the epicentral area of Nan’ao earthquake (M7.5), the northeastern South China Sea

Qiu

Zhao

et al. 2006

CHINESE SCI BULL

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1918 Nan'ao earthquake (M7.5) occurred in the northeast coastal areas of Guangdong Province. With the seismogeological survey of the epicentral area and history materials analyses, the earthquake epicenter was estimated to locate in the intersection part of the Binhai fault zone (Littoral) and Huanggangshui fault, which strikes NEE and NW, respectively. The activities of the NEE-striking thrust fault and NW-striking extensional fault that were attributed to 1918 Nan'ao earthquake occurred in the Dongshan Island of the epicentral area; they reflected the focal stress field with compression in NW-SE direction and extension in NE-SW direction. The isoseismal contour of seismic intensity X shows a shape of 'X' composed of two mutually overlapping ellipses with two axes striking NEE and NW, respectively, and such shape implies that the occurrence of this earthquake is controlled by a pair of conjugate seismotectonic faults constituted by the NEE-striking Binhai fault zone and the NW-striking Huanggangshui fault. The Binhai fault zone is a dominant seismogenic structure, and the NW-striking Huanggangshui fault is the subdominant one. The onshoreoffshore deep seismic profile that crossed the epicentral area and was perpendicular to the strike of the Binhai fault zone was obtained. According to the analyses of the seismic data, the Binhai fault zone is defined as a low velocity zone with SE dip-slip in the crustal structure section. The Binhai fault zone is a boundary fault between the South China subplate and South China Sea subplate. The crust structure on the northwest side of Binhai fault zone is a normal continental crust with a thickness of 30 km, and the one on the southeast side of the fault zone is a thinning continental crust with a thickness of 25-28 km. The Binhai fault zone is an important seismogenic fault and also is an earthquake-controlling fault. The intersection part between the Binhai fault zone and the low velocity zone of upper crust is advantageous to stress concentration and strain energy accumulation, and presents the deep dynamic conditions for the earthquake's pregnancy and occurrence.

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Section: Characteristics Of Crustal Structure In Epicentral Area and mentioning

confidence: 99%

Characteristics of the crustal structure and hypocentral tectonics in the epicentral area of Nan’ao earthquake (M7.5), the northeastern South China Sea

Qiu

Zhao

et al. 2006

CHINESE SCI BULL

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“…Deep seismic phases such as Pg, Pc, Pn and PmP were identified. A crustal structure model along the profile was obtained by ray tracing and travel time modeling [10] . Good results were achieved.…”

Section: Onshore-offshore Seismic Experiments In Northern South China Seamentioning

confidence: 99%

The application of large volume airgun sources to the onshore-offshore seismic surveys: implication of the experimental results in northern South China Sea

et al. 2007

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Onshore-offshore seismic experiments were carried out for the first time in northern South China Sea using large volume airgun sources at sea and seismic stations on land. The experimental results indicate that seismic signals from the new airgun array of R/V Shiyan 2 can be detected as far as 255 km. The signal effective area reaches nearly 50000 km 2 , which covers Hong Kong and Pearl River Delta. Compared with the old airgun array, the signal amplitude, propagation distance and effective area of the new airgun array have been increased notably, which demonstrates that the upgrade of the airgun source was successful. Comparisons with previous experimental results in other regions show that the shooting effect of the new airgun array is similar to those best airgun sources in the world. Especially, it is a new breakthrough in using the permanent seismic stations onshore to record long distance airgun signals offshore, which has great significance to the realization of the "seismic radar" concept and the 3D seismic surveys of crustal structure in coastal areas.airgun source, seismic station, onshore-offshore seismic survey, crustal structure, northern South China SeaThe earliest marine artificial seismic sources were simply a copy of the explosive sources on land, but it was soon discovered that the explosive sources had many disadvantages when underwater was used, e.g., difficult to operate, dangerous to handle, unable to auto-work continuously, and severe pollution to the environment. Especially because of the harmful effects on fishes and marine mammals, it is forbidden by law to use explosives in many international waters. Afterwards many marine sources have been invented and tested. Among them, the airgun has far surpassed the others in popularity. Its principle is to release suddenly high pressure air into water and produce seismic waves like small explosives. The airgun sources in early stage used only a single airgun and their output energy was small. Later on, airgun array sources were developed which consisted of many airguns. By careful designing, the primary pulse of airguns was enhanced and the bubble pulse was suppressed. Therefore, the airgun array was widely used in marine seismic surveys and occupied gradually the dominant position. Now, 95% of the marine seismic sources are airgun array sources [1] . OCEANOLOGYMost marine seismic surveys are MCS surveys to explore the detailed structure of sedimentary layers in oil-and-gas basins. Fewer are the wide angle reflection

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“…Further into the South China block, there are the similar Hengyang, Maoming, Sanshui, and Nanxiong Basins. According to the available information, the basins are Cenozoic basins, with the structure, sequence, and rock geochemistry demonstrating obvious tensional features and constituting a large-scale regional extensional system (Zhan et al, 1993;Zhao et al, 2004;Peng et al, 2007;Ding et al, 2005).…”

Section: Introductionmentioning

confidence: 98%

Seismic facies response of tectonics and direction of block movement in the northeastern South China Sea

2010

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The close relationship between the structure, evolution, and resources environment of the South China Sea is a current research focus and also a focal point of our study. In this paper, we use regional seismic sections to analyze the relationship between seismic facies and the structure and tectonic evolution of the northeastern South China Sea and propose new points about the structure and the direction of block (land mass) motion. First, the tectonic features are clear and can be divided into five different structural units which are both linked and independent of each other. Second, it doesn't matter if the South China Sea basin pattern is extensional, weakly compressive, or strongly compressive, the regional tectonic stress field is unified. For the first time we find that two shallow subduction zones are recognized in the seismic profiles. All the tectonic blocks have accordion-fold-style structures, converging in the east, and the South China Sea exhibits different stages of basin development: growth, maturity, end, and termination. The block subduction and regional block dip directions are all aligned with the regional stress field.

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An Analysis on Deep Crustal Structure Along the Onshore‐Offshore Seismic Profile Across the Binghai (Littoral) Fault Zone in Ne South China Sea

Cited by 32 publications

References 9 publications

Characteristics of the crustal structure and hypocentral tectonics in the epicentral area of Nan’ao earthquake (M7.5), the northeastern South China Sea

Characteristics of the crustal structure and hypocentral tectonics in the epicentral area of Nan’ao earthquake (M7.5), the northeastern South China Sea

The application of large volume airgun sources to the onshore-offshore seismic surveys: implication of the experimental results in northern South China Sea

Seismic facies response of tectonics and direction of block movement in the northeastern South China Sea

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