Huazhong Tectonomechanical Research Center

Wuhan, China

Huazhong Tectonomechanical Research Center

Wuhan, China
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Wang J.,China Earthquake Administration | Li X.,Wuhan University | Du C.,China Earthquake Administration | Zeng Z.,Chongqing Three Gorges University | Zeng Z.,Huazhong Tectonomechanical Research Center
Earth Science Frontiers | Year: 2017

Using the aerial methane concentration data extracted from the Atmospheric Infrared Sounder (AIRS) on the NASA Aqua satellite, and air temperature data recorded at the Kangding and Guza earthquake precursor stations, we studied the characteristics of the atmospheric methane concentration and temperature changes before and after the Wenchuan MS 8.0 earthquake in the Longmenshan area, and correlation between the changes. Our results show that there was a significant increase in methane concentration in the air of the Songpan-Ganzi block since 2004, and the increase was significantly influenced by the tectonic activities. As earthquake neared, areas of high methane concentration gradually converged towards the west side of the epicenter from both ends of the Longmenshan faults zone, and the methane concentration reached its peak value when the earthquake occurred. The trend of methane concentration change matched that of the temperature change, but because more time (1-2 days) was needed for the methane to transport from underground to the earth surface and ultimately released to the air, methane concentration reached its peak value slightly later than did the temperature. In conclusion, we discussed the mechanism of the methane concentration change before the earthquakes, and determined that the release of methane was connected with the stress state of the deep crust-mantle as well as micro fracture generation and expansion. © 2017, Editorial Office of Earth Science Frontiers. All right reserved.

Sun Z.,Wuhan University | Sun Z.,Huazhong Tectonomechanical Research Center | Zeng Z.,Wuhan University | Zeng Z.,Huazhong Tectonomechanical Research Center | And 8 more authors.
Journal of Asian Earth Sciences | Year: 2017

New results, in combination with previously published ones, reveal that when the Stress Exponent of the Competent layer (SEC) ranges from 1 to 10 (1. <. n. <. 10), Pinch-and-Swell structure Rheology Gauge (PSRG) can only be available under the condition that the Viscosity ratio between the Competent layer and its corresponding Matrix layer (VCM) is larger than 10. Therefore, we made the attempt to calculate the viscosity ratio of pinch-and-swell structure of competent layer to the related matrix and stress exponent. Based on this knowledge, we applied this gauge to calculate SECs and VCMs of eight types of pinch-and-swell structures, which are widely developed in the Taili area of the west Liaoning Province in China. Statistical analysis of the SEC resulted in intervals of four types of competent layers, that is, Medium-scale Granitic coarse-to-pegmatitic Veins, Small-scale Augen Granite aplite Veins, Small-scale Granite aplite Veins, and Small-scale Augen Quartz-K-feldspar veins, with intervals of [3.50,. 4.63], [2.64,. 4.29], [2.70,. 3.51], and [2.50,. 3.36] respectively. The preferred intervals of VCM of the five types of pinch-and-swell structures, Small-scale Augen Granite aplite Veins + Fine-grained Biotite-Hornblende-plagioclase Gneiss, Medium-scale Granitic coarse-to-pegmatitic Veins + Fine-grained Biotite-Hornblende-plagioclase Gneiss, Small-scale Augen Granite aplite Veins + medium-to-fine-grained granitic gneiss, Medium-scale Granitic coarse-to-pegmatitic Veins + medium-to-fine-grained granitic gneiss, and Small-scale Augen Granite aplite Veins + fine-grained biotite-plagioclase gneiss, are [19.98,. 62.51], [15.90,. 61.17], [26.72,. 93.27], [22.21,. 107.26], and [76.33,. 309.39] respectively. The similarities between these calculated SEC statistical preferred intervals and the physical experimental results verify the validity of the PSRG. The competent layers of the pinch-and-swell structures were presented in this study as power-law flow with SEC values that increased with the thickness of the layer. Grain-size plays an important role in the rheology of pinch-and-swell structures. The results offer a case for the application of PSRG and determine the key rock rheological parameters of North China Craton for future related studies. © 2017 Elsevier Ltd.

Zeng Z.,China Three Gorges University | Zeng Z.,Wuhan University | Zeng Z.,Huazhong Tectonomechanical Research Center | Sibgatulin V.G.,Russian Academy of Sciences | And 8 more authors.
Earth Science Frontiers | Year: 2013

At 11: 55 of May 7, 2013, Victor G. Sibgatulin in the Special Engineering Design Bureau, Krasnoyarsk Scientific Center, Siberian Department of Russian Academy of Science, informed Zeng Zuoxun, the first author of the paper, that the natural electromagnetic pulse anomalies indicated that there would be an earthquake of magnitude about MS 6 in the west or east direction of the Wuhan City of China. At 22: 20 of May 7, 2013, Song Song in the Professional Secondary School of Pingyuan County, Dezhou, Shandong, China, informed Zeng Zuoxun about an earthquake prediction cooperated with Song Kefu, based on his observation of a precursory halo lasted for 10 minutes beginning from 11 o'clock of May 7, 2013. They predicted that an earthquake with magnitude ranging from MS 5.5 to 6.2 would occur in 7 days in the adjoining area of Tibet, Xinjiang and Qinghai of West China. On the basis of the comprehensive analysis of the prediction of Victor Sibgatulin and the prediction of Song Song and Song Kefu, and an observation for the locations of a degasification of the earth in the Naqu, Tibet by Zeng Zuoxun himself, the first author made a prediction for an earthquake around MS 6 in 10 days in the area of the degasification point(31.5°N, 89.0°E)and E-mailed the prediction to Song Song, Wang Jie and Pan Lili at 0: 54 of May 8, 2013. He offered another degasification point (31°N, 86°E) for the epicenter prediction at 8: 34 of the same day. At 18: 54: 30 of May 15, 2013, an earthquake of MS 5.2 occurred in the Nima County, Naqu, China. The epicenter is located at 31.6°N, 86.5°E. The focus is at the depth of 10 km. The occurring time of the Nima earthquake fell into the time window of the prediction made by Zeng Zuoxun and by Song Song and Song Kefu. The epicenter of the Nima earthquake fell into the area around the second degasification point. The Nima earthquake fell basically into the predicted magnitude by Victor Sibgatulin, by Song Song and Song Kefu and by Zuoxun Zeng. The significance of the successful imminent prediction of the Nima earthquake is that it is a successful case of the cooperation between two countries and among three institutions. It further proves that the successful prediction needs comprehensive analysis with multiple-method information. It is indicated by the section of the crust in the area around the epicenter and by the research of the active faults in the area that the NNW-trending Laiduo-Cuomai fault is the triggering fault of the Nima earthquake, that the concentration and storage of the earthquake energy was closely related to the high conductive-low velocity layer in the mid-crust and that the current stress field controlling the fault activities in the Tibet area is of characteristics of compression in SN direction and extension in EW direction.

Jin W.,Huazhong University of Science and Technology | Li Y.,Huazhong University of Science and Technology | Zhao W.,Guanzhou Institute of Road Engineering | Zheng W.,Huazhong University of Science and Technology | Zheng W.,Huazhong Tectonomechanical Research Center
Huazhong Keji Daxue Xuebao (Ziran Kexue Ban)/Journal of Huazhong University of Science and Technology (Natural Science Edition) | Year: 2015

To check the efficiency of distributed optic fiber sensor in concrete component for stress, strain, and inner cracks, an experimental study was conducted by testing a standard 2 m beam. This study based on the physics of Brillouin scattered light, that is, the frequency of scatter has linear relation to the strain. In addition, the embedded optic fiber was adopted, and the beam was tested on the mechanical universal testing machine. The optical fiber analyzer was used for pumping the laser, inputting the detective pulse, and reading the scatter. The data's analysis was done by the analyzer to get the stress and strain and output a text file. During the testing process, traditional strain gauge was used for comparative study. Two types of optic sensor, naked optic fiber and glassfiber reinforced plastic (GFRP) intelligent reinforce bar, were checked. The result shows that the two types of optic sensor are effective for measuring the strain of concrete and detecting the cracks, and naked optic fiber is more sensitive than GFRR intelligent reinforce bar. © 2015, Huazhong University of Science and Technology. All right reserved.

Liu W.,Hubei University | Zeng Z.-X.,Hubei University | Zeng Z.-X.,Huazhong Tectonomechanical Research Center | Li S.-F.,Hubei University | And 3 more authors.
Geology in China | Year: 2014

The Yangyingzui W-Mo-Cu polymetallic deposit is located in the middle segment of the northeast Guangxi metallogenic belt. Orebodies occur within the porphyry and skarn of the contact zone, and mineralization is closely related to.the Yanyingzui porphyry. Up till now, however, there have been no precise data concerning the porphyry mineralization age of this ore deposit. The authors conducted the LA-ICP-MS zircon U-Pb chronologic study of the mineralized granite porphyry and granodiorite porphyry in the Yanyingzui W-Mo-Cu deposit and obtained ages of (426.2±2.3) Ma and (426.9±2.3) Ma, indicating that the porphyry is a product of tectonic-magmatic activity during the Caledonian. Combined with regional tectonic evolution, contrastive study of the timing for diagenesis and mineralization as well as geological characteristics of ores, it is suggested that the ore-forming and igneous activities of the Yangyingzui W-Mo-Cu polymetallic deposit occurred during Late Silurian, when the tectonic setting of the deposit was in the transition period from collision orogeny compression to extension. The Yangyingzui W-Mo-Cu polymetallic deposit has the same metallogenic age and same structural setting as the northeast Guangxi W-Mo mineralization belt, implying that the probable existence of an intense W-Mo-Cu mineralization during Caledonian period in northeast Guangxi. In addition, the NE-trending tectonomagmatic belt, the porphyry body zone and the periphery of the mineralization area are favorable areas in search for porphyry-skarn-type W-Mo-Cu polymetalic deposits, homologous series deposits and conceaned ore deposits, and hence more attention should be paid to the exploration and evaluation of the study area in the future.

He C.,Wuhan University | He C.,Huazhong Tectonomechanical Research Center | Li X.,Huazhong Tectonomechanical Research Center | Li X.,Wuhan University | And 4 more authors.
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | Year: 2015

At 08:04 of August 31st, 2013, an earthquake with a magnitude of Ms 5.9 occurred in Shangrila county of Tibetan Autonomous Prefecture, Yunnan Province (28.1°N, 99.4°E). The depth of the hypocenter is 10 km. The study area is seismically active in history and prone to earthquake in northwestern Yunnan. Then the focal mechanism solutions show that the Diqing Ms 5.9 earthquake is of normal faulting with dextral strike-slip and the attitude of the NW nodal plane is consistent to the Deqin-Zhongdian fault. In this paper, we discuss the bouguer anomaly near the epicenter using EIGEN-6C2 model, and the epicenter is located at the Moho depth undulating position, and place where the crustal thickness is unstable. From the profile of P wave velocity and crustal structure, we know that low-velocity layer exists at the bottom of the upper crust, and the layer is likely to be closely related to seismic energy accumulating and storing. The joint location of the edge of the low-velocity (high conductivity) layer and the Deqin-Zhongdian fractures is the location for the focus to release the accumulating energy. This provides a new case of the three-level tectonic model for intra-plate earthquake. ©, 2015, China University of Geosciences. All right reserved.

Wang J.,Wuhan University | Wang J.,China Three Gorges University | Wang J.,Huazhong Tectonomechanical Research Center | Zhang X.,Wuhan University | And 8 more authors.
Earth Science Frontiers | Year: 2013

The effects of methane and other fluid on earthquake have widely attracted attention of the world after the Wenchuan earthquake(MS 8.0). Since most of the data used in observation and research were derived from surface or subsurface stations which are distributed scatteringly and are costly to be maintained, it is difficult to develop real-time monitoring in a large area. We studied the relationship between the variation of methane concentration and the abnormal temperature increasing of the atmosphere before the Lushan earthquake (MS 7.0) in the Longmenshan area, by using the methane concentration data extracted from Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite. The results show that we could find the emission of subsurface methane before earthquake from Atmospheric Infrared Sounder, which provides a new way to monitor the seismic precursor. Moreover, this research shows that the methane emission was closely related to the abnormal temperature increasing of the atmosphere before the earthquake. The methane emission anomalies were controlled by active fractures significantly. They mainly concentrated along the Longmenshan fracture zone, Xianshuihe fault, and Rongjing-Mabian fault. Finally, we discussed the mechanism of emission of methane and other fluid. It is considered that the emission of these fluids was attributed to the fracturing and fracture propagation in the upper crust in the pre-earthquake stage.

Liu G.,China Three Gorges University | Zeng Z.,China Three Gorges University | Zeng Z.,Wuhan University | Zeng Z.,Huazhong Tectonomechanical Research Center | And 5 more authors.
Earth Science Frontiers | Year: 2013

At 7: 45 of July 22, 2013, an earthquake occurred at the border between Minxian and Zhangxian of Dingxi City (34.5°N, 104.2°E), Gansu Province with magnitude of MS 6.6. The depth of the focus is 20 km. In this disaster, 95 people died, 1366 people were injured, and the total economic loss reaches 21 billion Yuan RMB. We review the imminent prediction process and basis for the earthquake using the fingerprint method created by the first author. We also discuss the triggering structure and the seismic mechanism of the earthquake. Nine channels or 15 channels of anomalous components-time curves can be output from the SW monitor for earthquake precursors (or simply SW monitor for short). These components include geomagnetic, geoelectric, crust stresses, resonance, and crust inclination components. When we compress the time axis, the output curves become different geometric images. The precursor images are different for earthquake in different regions. The alike or similar images correspond to earthquakes in a certain region. In this way, we can predict the location for a coming earthquake using the precursor images. This can be analogous to a person's definite fingerprint. We can find a person with a fingerprint. Therefore, the method predicting earthquake by using the precursor images is called fingerprint method. According to the 7-year observation of the precursor images and their corresponding earthquakes, we usually get the fingerprint 6 days before the corresponding earthquake. The magnitude prediction needs the comparison between the amplitudes of the fingerprints from the same channel. In this way, the fingerprint works a miracle that we can predict the three key elements of earthquake using single station data. At 10: 45 of July 15, 2013, the first author predicted that there would be an earthquake occurring on July 19, 2013, in Gansu (35.19°N, 103.69°E)with the magnitude of MS 5.1 on the basis of the comparison between the fingerprints from the channel 5 on July 14, and on June 2, 2013. The Minxian MS 6.6 earthquake occurred on July 22, 2013 indicates that the predicted epicenter is accurate, that the earthquake occurring time is delayed only 3 days, and that the magnitude is larger than the predicted magnitude by MS 1.5. In general, it is a successful imminent prediction. From the comprehensive analysis of the tectonic setting, the crust P wave velocity structures and the focus mechanism of the Minxian earthquake, we consider that the Lintan-Lixian left-lateral thrusting is its triggering and that the joint location of the edge of the low-velocity (high-conductivity) layer and the Lintan-Lixian fractures is the location for the focus to release the accumulated energy. This provides a new case of the three-level tectonic model for intraplate earthquake.

Pan L.,China Three Gorges University | Pan L.,Wuhan University | Pan L.,Huazhong Tectonomechanical Research Center | Zeng Z.,China Three Gorges University | And 5 more authors.
Earth Science Frontiers | Year: 2013

The infrasound monitors installed in the Three Gorges Reservoir Area by the Three Gorges Research Center for Geo-hazard of China University of Geosciences (Wuhan) had received abnormal signals before the onset of the Lushan earthquake (MS 7.0, April 20, 2013) and Yushu earthquake (MS 5.2, June 26, 2011). We analyzed the abnormal signals received by different stations using both Matlab filtration and wavelet analysis. The frequency of the precursory infrasonic signals predating the Lushan earthquake is mainly (0-4)×10-3Hz, and that of the Yushu earthquake is mainly (0-5)×10-3Hz. The amplitude of the precursory infrasonic signal increases with the earthquake magnitude. After we analyzed the time difference of the abnormal signals received by Yesanguan and Zigui stations and the distance between the epicenter and the stations, we calculated that the velocity of the precursory ultra-low frequency infrasonic wave of the Yushu earthquake is 6.4 m/s. To investigate the possibility of short-term and impending earthquake predictions, we developed a monitoring array, a big triangle array enclosing a small triangle array, to detect the location of the epicenter for the further researches.

Zeng Z.,China Three Gorges University | Zeng Z.,Wuhan University | Zeng Z.,Huazhong Tectonomechanical Research Center | Wang J.,China Three Gorges University | And 2 more authors.
Earth Science Frontiers | Year: 2013

Lushan Earthquake (MS 7.0, April 20, 2013) is another disastrous geological event along the Longmenshan earthquake fracture zone after 2008. This article reviews a successful medium-term prediction for the large Earthquake. It also gives the reason for the prediction of the epicenter. In the morning of November 25, 2012, the Committee for Predicting Natural Disasters of Chinese Geophysical Society discussed the Medium-Term earthquake prediction for the southwest China. Qingguo Geng, the director of the committee reviewed his prediction presented in April, 2012, that there would be a possible earthquake of MS 7.0 to MS 8.0 in the southwest China during the period of May, 2012 through May, 2013. Members attended the meeting agreed with the prediction time, but had different opinion in the location of the possible large earthquake in the southwest China. The first author made a presentation at the meeting. Zuoxun Zeng gave a definite location on his prediction map. It is located at the middle of the line linking Ya'an and Kangding, Sichuan Province. This prediction is made mainly according to two aspects. One is that two satellite local intense gravity anomalies with the same characteristics are appearing at the Wenchuan area and the west to Ya'an City, respectively. The other is that the Wenchuan earthquake only released the energy of the northeast part of the longmenshan fracture zone, this leads to the stress and energy concentration at the southwestern part of the fracture zone, especially at the southwestern end of the Longmenshan fracture zone with the abrupt gravity change, or abrupt change of density of the middle crust. The epicenter of Ya'an Earthquake (MS 7.0) is located at Lushan of Ya'an City, 80 km from the predicated location. The origin time of the quake is before May of 2013. The successful medium-term prediction of the Lushan earthquake has given us a good deal of enlightenment: as a geological process, earthquake should have its own regularity. A successful earthquake prediction needs comprehensive analysis by using information from different observations. Just because of this, the main need now is a national or international expert group with comprehensive analysis experience and an efficient information platform for seismic precursor. The data processing and update for the satellite gravity will be helpful to narrowing the area of the possible large earthquakes.

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