scholarly journals Lithospheric Equilibrium, Environmental Changes, and Potential Induced-Earthquake Risk around the Newly Impounded Baihetan Reservoir, China

2021 ◽  
Vol 13 (19) ◽  
pp. 3895
Author(s):  
Guangyu Fu ◽  
Yawen She ◽  
Guoqing Zhang ◽  
Yun Wang ◽  
Shanghua Gao ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Gravity Anomalies ◽  
Hydropower Station ◽  
Earthquake Risk ◽  
Coulomb Stress ◽  
Induced Earthquakes ◽  
Induced Earthquake ◽  
Free Air ◽  
Maximum Improvement ◽  
Baihetan Hydropower Station

The Baihetan hydropower station is the second largest hydropower station worldwide. It began to store water in April 2021. We conducted a dense hybrid gravity and GNSS survey at 223 stations, obtained the free-air and Bouguer gravity anomalies, inversed the lithospheric density structure, and calculated the isostatic additional force (IAF) borne by lithosphere in the reservoir area. Moreover, we studied the gravity change and Coulomb stress change around the Baihetan reservoir due to impoundment. The main findings are the following. (1) Hybrid gravity and GNSS observations significantly improved the spatial resolution of the gravity field, and the maximum improvement reached up to 150 mGal. (2) A new method for risk assessment of reservoir-induced earthquakes is proposed from the perspective of lithospheric equilibrium. It was found that there is an IAF of −30 MPa at approximately 20 km upstream of the Baihetan dam, and the risk of a reservoir-induced earthquake in this area warrants attention. (3) It was found that the Coulomb stress variation on the Xiaojiang fault near Qiaojia at a depth of 10 km exceeded the threshold for inducing an earthquake (0.1 bar).

scholarly journals Risk Assessment of Fracturing Induced Earthquake in the Qiabuqia Geothermal Field, China

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5977
Author(s):  
Kun Shan ◽  
Yanjun Zhang ◽  
Yanhao Zheng ◽  
Liangzhen Li ◽  
Hao Deng
Keyword(s):  
Principal Stress ◽  
Focal Mechanism ◽  
Maximum Principal Stress ◽  
In Situ Stress ◽  
Geothermal Field ◽  
Earthquake Risk ◽  
Maximum Magnitude ◽  
Induced Earthquakes ◽  
Induced Earthquake

In order to reduce the harm of induced earthquakes in the process of geothermal energy development, it is necessary to analyze and evaluate the induced earthquake risk of a geothermal site in advance. Based on the tectonic evolution and seismogenic history around the Qiabuqia geothermal field, the focal mechanism of the earthquake was determined, and then the magnitude and direction of in-situ stress were inversed with the survey data. At the depth of more than 5 km, the maximum principal stress is distributed along NE 37°, and the maximum principal stress reaches 82 MPa at the depth of 3500 m. The induced earthquakes are evaluated by using artificial neural network (ANN) combined with in-situ stress, focal mechanism, and tectonic conditions. The predicted earthquake maximum magnitude is close to magnitude 3.

Microseismic monitoring of columnar jointed basalt fracture activity: a trial at the Baihetan Hydropower Station, China

2014 ◽  
Vol 18 (4) ◽  
pp. 773-793 ◽  
Author(s):  
Bing-Rui Chen ◽  
Qing-Peng Li ◽  
Xia-Ting Feng ◽  
Ya-Xun Xiao ◽  
Guang-Liang Feng ◽  
...  
Keyword(s):  
Microseismic Monitoring ◽  
Hydropower Station ◽  
Columnar Jointed Basalt ◽  
Baihetan Hydropower Station

5. Gravity and the figure of the Earth

2018 ◽  
pp. 69-91
Author(s):  
William Lowrie
Keyword(s):  
Accurate Determination ◽  
Measurement Techniques ◽  
Gravity Anomalies ◽  
Dynamic Processes ◽  
The Core ◽  
The Earth ◽  
Free Air ◽  
Figure Of The Earth ◽  
Free Air Gravity

‘Gravity and the figure of the Earth’ discusses the measurement of gravity and its variation at the Earth’s surface and with depth. Gravity is about 0.5 per cent stronger at the poles than at the equator and it first increases with depth until the core–mantle boundary and then sinks to zero at the Earth’s centre. Using satellites to carry out geodetic and gravimetric observations has revolutionized geodesy, creating a powerful geophysical tool for observing and measuring dynamic processes on the Earth. The various measurement techniques employed fall in two categories: precise location of a position on the Earth (such as GPS) and accurate determination of the geoid and gravitational field. Bouguer and free-air gravity anomalies and isostasy are explained.

Empirical Determination of the Gravity Anomaly Covariance Function in Mountainous Areas

1980 ◽  
Vol 34 (3) ◽  
pp. 251-264 ◽  
Author(s):  
Gerard Lachapelle ◽  
K. P. Schwarz
Keyword(s):  
Gravity Anomaly ◽  
Covariance Function ◽  
Physical Geodesy ◽  
Gravity Anomalies ◽  
Mountainous Areas ◽  
The North ◽  
Regression Parameters ◽  
Free Air ◽  
Vening Meinesz ◽  
Free Air Gravity

An evaluation of the empirical gravity anomaly covariance function using over 95 000 surface gravity anomalies in the North American Western Cordillera was carried out. A regression analysis of the data exhibits a strong and quasi-linear correlation of free air gravity anomalies with heights. This height correlation is removed from the free air anomalies prior to the numerical evaluation of the gravity anomaly covariance function. This covariance function agrees well with that evaluated previously by the authors for the remainder of Canada. A possible use for such a covariance function of ‘height independent’ gravity anomalies in mountainous areas is described. First, the height independent gravity anomaly at a point of known height is evaluated by least squares prediction using neighboring measured height independent gravity anomalies. Secondly, the part caused by the height correlation is calculated using linear regression parameters estimated previously and added to the predicted height independent gravity anomaly to obtain a predicted standard free air anomaly. This technique can be used to densify the coverage of free air anomalies for subsequent use in integral formulas of physical geodesy, e.g., those of Stokes and Vening Meinesz. This method requires that point topographic heights be given on a grid.

Free air gravity anomalies over the oceans from Seasat and GEOS 3 altimeter data

Eos ◽  
1987 ◽  
Vol 68 (2) ◽  
pp. 17 ◽  
Author(s):  
G. Balmino ◽  
B. Moynot ◽  
M. Sarrailh ◽  
N. Valès
Keyword(s):  
Gravity Anomalies ◽  
Altimeter Data ◽  
Free Air ◽  
Free Air Gravity

Mechanical anisotropy of columnar jointed basalts: An example from the Baihetan hydropower station, China

2014 ◽  
Vol 175 ◽  
pp. 35-45 ◽  
Author(s):  
Quan Jiang ◽  
Xia-ting Feng ◽  
Yossef H. Hatzor ◽  
Xian-jie Hao ◽  
Shao-jun Li
Keyword(s):  
Mechanical Anisotropy ◽  
Hydropower Station ◽  
Baihetan Hydropower Station
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