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Collapse experiment and numerical simulation of a slope under strong earthquake
Published in Charlie C. Li, Xing Li, Zong-Xian Zhang, Rock Dynamics – Experiments, Theories and Applications, 2018
Earthquake and engineering-induced seismicity (or called artificial earthquake) could cause disasters. In general, the magnitude of artificial earthquakes is smaller than natural earthquakes. The greater the magnitude is, the more energy is released with the greater destructive power. In general, an earthquake, whose magnitude is equal to or greater than six, is called a strong earthquake, such as the strong earthquake of magnitude 7.1 in Yushu County of Qinghai in April 14, 2010. If the magnitude is greater than or equal to 8, it is called a huge earthquake, such as the Wenchuan earthquake of the magnitude 8 in May 12, 2008. Wenchuan and Yushu are located in mountainous areas, and the landform of both is featured in high mountain slopes which are steep slopes and contain faults and joints. The Wenchuan earthquake has the characteristics of high magnitude, fault trusting diastrophism and long main shock duration, which results in disasters like surface rupture, landslide and liquefaction. Among them, the landslides have the following characteristics (Wang 2008; Yin 2006). The first one is the large number of landslides with large distribution density. The second one is the huge influence area with serious disaster loss. The third is the large scale of earthquake-induced landslides. And the fourth is that the landslide distribution is obviously affected by the fault rupture.
Observation of microearthquakes in the Atotsugawa fault region, central Honshu, Japan - Seismicity in the creeping section of the fault
Published in H. Ogasawara, T. Yanagidani, M. Ando, Seismogenic Process Monitoring, 2017
Temporary observations of earthquakes in the Atotsugawa fault zone have revealed detailed seismicity along the fault system. Seismic activity is concentrated along the major three faults of the fault system. Deeper cutoff depth of seismicity shows a clear concave shape along the fault system with greatest depths of 16–18 km below the creeping section. Besides, seismicity is very low in the upper 7–8 km below the creeping section. On both sides of the low seismicity region, earthquake clusters sometimes occur and seismicity is high. However, GPS surveys suggest that the fault is locked and forms a shear zone. This change in seismicity along the fault system possibly indicates the change in asperities along the fault and eventually irregular deformation along it. Thus, detailed surveys of seismicity along active faults can be related to the nucleation of large inland earthquakes. The result may also be useful in calculating strong motions by assuming asperities on the fault plane for future large earthquakes
Seismic hazard analysis: An overview
Published in Mariana R. Correia, Paulo B. Lourenço, Humberto Varum, Seismic Retrofitting: Learning from Vernacular Architecture, 2015
J.F.B.D. Fonseca, S.P. Vilanova
Earthquakes are not randomly distributed in space. The Earth’ crust is composed of large tectonic plates that move slowly on top of the molten rocks that lay underneath, and the earthquakes concentrate in the boundaries were the plates collide, spread or slide against each other. Plate tectonics, derived in the 1960’s and now observed directly through satellite geodesy, provides a rationale for most of the planet’s seismicity. The strongest earthquakes (magnitudes 8.5 and above) occur at subduction zones, where oceanic plates dive underneath less dense continental crust. This process is taking place around the Pacific Ocean, leading to strong earthquakes in Japan, Chile and Alaska, for instance. In the Indian Ocean, Java and Sumatra (Indonesia) are also the locus of strong subduction earthquakes. Regions of continent-continent collision are also prone to large earthquakes, typically in the magnitude range 7–8.5. These plate boundaries are broader, with the deformation spreading over a belt that can reach ∼1000 km in width. Examples are the continental collision of India with the Eurasian plate. Transcurrent plate boundaries (transformfaults) where tectonic plates slide past each other, such as the San Andreas Fault or the North Anatolian Fault, generate maximum earthquakes in the range 7–8.
Catalogue of real-time instrumentation and monitoring techniques for tailings dams
Published in Mining Technology, 2021
Seismicity can present itself naturally or be induced by mining activities. Naturally through earthquakes, the regional susceptibility to seismic behaviour is often understood and accounted for in the design. Regardless, monitoring techniques are employed to help understand the magnitude, distance to source, and the potential influence that these natural events may have on current activities. Mining activities have also been empirically proven to cause induced seismicity, from triggers such as underground rock burst, oil and gas extraction, fluid injection and hydraulic fracturing, and pore pressure increase in faults.