Abstract A seismic reflection profile crossing the San Andreas fault zone in central California was conducted 1978. Results are complicated by extreme lateral heterogeneity and low velocities zone. Other evidence for severe velocity change across lies hypocenter bias nodal plane distortion earthquakes on fault. Conventional interpretation processing methods data hard-pressed this situation. Using inverse ray method of May Covey (1981), with an initial model derived from a variety impedance...

Abstract Accurate radar cross section (RCS) measurements are challenged by background-target coupling, such as interactions with the ground or support structures. This paper introduces a method using three-dimensional (3D) imaging to isolate and measure target scattering characteristics. By utilizing high-resolution 3D algorithms, separates target’s scatterers from background noise, enhancing RCS measurement accuracy. Experimental results show this approach reduces coupling effects,...

Four distinct granitic series developed during the evolution of Archean Abitibi Southern Volcanic Zone (SVZ): (1) A minor synvolcanic tonalite–trondhjemite–granodiorite (TTG) was emplaced at ~2700 Ma, which has extremely low K 2 O (<1.5 wt.%), Rb (<50 ppm), and Sr (<200 higher Nb, Y, Sc, flat rare-earth-element (REE) patterns, negative Eu anomalies. (2) voluminous tonalite – granodiorite granite quartz monzonite (TGGM) syntectonically ~2695–2685 displays (1–3 (10–50 Ba (<1000 U,...

40 Ar/ 39 Ar mineral age spectra of granitic and metamorphic rocks, in conjunction with existing conventional zircon geochronology, indicate that at least two major late Archean thermal events affected tectonic blocks the Abitibi Southern Volcanic Zone (SVZ) juxtaposed Pontiac Subprovince. The earlier activity (2690–2670 Ma) was accompanied by intrusion voluminous syntectonic plutons caused low-pressure, greenschist-facies metamorphism SVZ intermediate-pressure second event (2660–2630 coeval...

The location of buried faults, especially in the near surface, is considerable importance with respect to earthquake prediction, disaster reduction, and city planning. Electrical resistivity tomography (ERT), which can have an effective depth investigation several hundred meters, has been applied detection faults urban areas on China mainland since 2001, proven be one most powerful geophysical tools for this application. To better facilitate exploration we present study Zhangdian-Renhe...

Research Article| September 01, 1990 Geobarometry, differential block movements, and crustal, structure of the southwestern Abitibi greenstone belt, Canada Rui Feng; Feng 1Department Geological Sciences, University Saskatchewan, Saskatoon, Saskatchewan S7N 0W0, Search for other works by this author on: GSW Google Scholar Rob Kerrich Author Article Information Publisher: Society America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print 0091-7613 Geology (1990) 18 (9): 870–873....

Six granitic magma series were generated sequentially during evolution of the Archean Abitibi greenstone belt and adjacent high-grade metasedimentary Pontiac subprovince. Minor synvolcanic tonalite-trondhjemite granodiorite intrusions (the TTG series) emplaced at approximately 2700 Ma; fresh samples have whole-rock delta 18 O values 5.6 + or - 0.5 per mil (1Sigma ), retain magmatic fractionations between quartz feldspar (1.5 0.5), are characterized by Au abundances 2.1 1.6 ppb ). Altered...

Abstract The application of three‐dimensional inversion gravity and magnetic fields is very important not only in geophysical researches, but also the study geological structures. A formula potential field frequency‐domain, developed by Parker 1973, can be used as a rapid effective algorithm inversion. technique has been improved then Oldenburg, Sprenke, Feng others. In addition to brief introduction Parker's its applications, this paper includes following five parts: basic computational...

Abstract The apparent resistivity of rock usually has obvious variations during its crack under the applied pressure. Its anomalous pattern is closely related with experimental conditions. This paper presents an study on this problem. A magnetite‐quartzite sample was compressed uniaxially. cracks in were produced by cyclic compression processes (several loading‐unloading cycles) and salt solution injected into sample. Resistivity tomography introduced to simulating experiment. series true...

The time‐dependent behaviour of high rockfill dams is complex and not easy to accurately predict. Many discrepancies were revealed by the comparison observed deformation histories different dams, some did correspond general law. Field monitoring therefore an effective method for understanding dam behaviour. In this paper, actual measured data resulting from continuous Maoergai Qiaoqi are analysed. These two have similar heights, crest lengths, alluvium overburden thicknesses. Our aim explain...

Failure during the start and brake processes of a 1.5 MW horizontal axis wind turbine blade was examined using measured field with fluid-structure coupling. The maximum displacement stress angular acceleration process were 7.14% 16.27%, respectively, larger than those without acceleration, whereas braking they 37.71% 26.96% larger, acceleration. Further, had greater impact on second-order frequency vibration first-order, significantly impacting process. dynamic amplitude blades starting 4.35...

Basing on the geological mining condition under villages at Xiaotun Mine, according to existing theories of strip-partial mining, using method analyzing field measurements date and calculating by empirical formula, safe range retained widths can be confirmed, schemes for different coal pillar designed, optimum scheme worked out; then stability each will calculated through numerical simulation analysis, providing basis appropriately selecting scheme; this basis, prediction surface movement...

After mining, a dynamic distribution of mining fissure elliptic paraboloid zone in the overlying stratum would be formed. Based on rock mechanics, seepage flow mass transfer theory and elastic-plastic theory, coal-rock deformation equation, mixture gas equation diffusion are deduced. Combined with various boundaries, initial conditions, multi-field coupling mathematical model is obtained. The provides theoretical basis for numerical simulation drainage system layout.

Abstract We used the method of resistivity tomography to earthquake monitoring. Through inversion apparent resistivity, image true was reconstructed. It reveals nature variations relevant physical parameters during seismogenic process. At two stations in North China, Baodi and Changli, obvious anomalous changes appeared tomograms 6 days before earthquakes M L 5.0 4.4, respectively, which occurred Tangshan on 14 April 1998. The distribution images station showed a new pattern, i.e. an ordered...