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Simulation of strong motions and surface rupture of the 2014 Northern Nagano Earthquake
Published in Charlie C. Li, Xing Li, Zong-Xian Zhang, Rock Dynamics – Experiments, Theories and Applications, 2018
N. Iwata, R. Kiyota, K. Adachi, Y. Takahashi, Ö. Aydan, F. Miura, T. Ito
The 1999 Chi-chi earthquake and the 1999 Kocaeli earthquake damaged many important structures due to surface rupture as well as high strong motions induced by the earthquake faults, which indicated the significance of displacement and inclination of ground surface on the response and damage of structures. Generally strong motions are estimated by Green’s function method and fault displacement is estimated from geological surveys. However an earthquake occurs by rupture of earthquake source fault. When the displacement is large, it will reach the ground surface and appear as a surface rupture. Therefore, ideal analytical model should be able to simulate a fault rupture process and estimate displacement and strong motion at the same time. Fault rupture simulations by Finite Difference Method (FDM), Finite Element Method (FEM) and Boundary Element Method (BEM) are generally carried out. However, they have not become practical as analytical results greatly vary according to assumed initial stress conditions and modeling of fault rupture.
Natural Events: Seismic And Geotechnical Aspects
Published in Maurizio Cumo, Antonio Naviglio, Safety Design Criteria for Industrial Plants, 2019
Settlements of the ground surface have been observed during major earthquakes. They are determined by the following phenomena. Tectonic movements (surface faulting). Movements of tectonic structures, propagating up to the surface, may cause horizontal and vertical displacements. Geologic studies are required in order to investigate those faults which, during major earthquakes, may determine surface ruptures and displacements. Construction site for major hazard industrial plants must be chosen far from these faults.Compaction of unsaturated granular soils. Vibrations induced in soil deposits or earth structures (backfills), determine compaction with settlements at the surface. Settlements due to compaction phenomena can be evaluated correlating soil properties with earthquake-induced shear stresses.69 The soil properties, as for liquefaction analysis, are determined by in situ tests (normally SPT) or laboratory test (cyclic triaxial or simple shear tests). The dynamic shear stresses are evaluated by simplified procedures62 or by dynamic response analyses.16Dissipation of pore water pressure build-up in saturated granular soils. As just described above, dynamic shear stresses generate an increment of pore water pressure in cohesionless saturated soil deposits. Even if liquefaction does not occur, the subsequent dissipation of the pore water pressure increment determines a volume reduction and settlements. Also in this case, settlements can be evaluated correlating soil properties and induced dynamic shear stresses.69
The potential for palaeoseismic and palaeoclimatic reconstructions from Lake Tennyson, North Canterbury, New Zealand
Published in New Zealand Journal of Geology and Geophysics, 2023
John-Mark Woolley, Andrew Lorrey, Paul Augustinus, Patricia S. Gadd
The Spenser Mountains and St James Range are an extension of the Southern Alps ‘Main Divide’ which extends into the northern South Island. Lake Tennyson sits in the centre of this mountainous area and feeds a major catchment of the Clarence River that flows south and then east to the Pacific Ocean (Figure 1). The upper Clarence River flows south for 10 km and terminates in a delta on the northern side of the lake basin, which indicates sediment input to the lake from upstream sources. The main Clarence River exits the southeast corner of Lake Tennyson over a bedrock sill underpinning incised late Pleistocene glacial deposits. It is joined by flows from other catchments to the south and west of the lake, including Princess Stream, less than 1.5 km downstream of the lake outlet. The Lake Tennyson basin intersects the Marlborough Fault System, which is influenced by several faults (McCalpin 1992) that link the Alpine Fault in the south with the convergent Hikurangi subduction margin to the north (Figure 1) (Lamb and Bibby 1989). The Marlborough Fault System accommodates ∼38 mm/yr of relative plate motion, mostly through oblique, dextral transpressional strike-slip motion (Yang 1991), and is largely accounted for by the Awatere, Clarence and Hope faults in addition to the northern Alpine Fault (Lamb and Bibby 1989). Numerous active faults within the region are associated with shallow earthquakes that commonly result in surface rupture (Rattenbury et al. 2006). A main trace of the Awatere Fault crosses directly through Lake Tennyson (Figure 1), and steep, unvegetated slopes around the lake show evidence of active rock slides and sediment transport pathways.