On some recent achievements of earthquake simulation

AbstractThis paper presents some recent achievements of earthquake simulation, which is divided into the seismic wave propagation simulation and the seismic structure response simulation. These achievements are based on rigorous mathematical treatment of continuum mechanics problems, and numerical algorithms of solving the problems are developed. A multi-scale analysis method is developed for the seismic wave propagation simulation; numerical dispersion is reduced by introducing a new discretization scheme. A smart treatment of crack initiation and propagation is developed for the seismic structure response simulation, so that a numerical experiment is made for failure processes by using numerous samples of one structure

Integrated Earthquake Simulator to Generate Advanced Earthquake Disaster Information

Realistic simulation of possible earthquakes is crucial for producing a rational counter plan against earthquake disasters. This paper presents such a simulation method, the Integrated Earthquake Simulator (IES), which uses a computer-based high-resolution strong ground motion (SGM) simulator and a Virtual Reality (VR) city constructed from GIS/CAD data. The IES is an integrated computer system that is intended to simulate all phases of earthquakes numerically: earthquake hazards, earthquake disasters, and human and social actions against earthquake disasters. An efficient combination of GIS/CAD data and numerical simulation tools for each phenomenon on this computer system can achieve integrated earthquake simulation. This paper presents the methodology of reconstruction of a VR city and the IES prototype. An example of a VR city model is reconstructed and some earthquake disaster simulations are undertaken to examine the IES performance

Development of higher order particle discretization scheme for analysis of failure phenomena

This paper presents the higher order extension of Particle Discretization Scheme (PDS) and its implementation in FEM framework (PDS-FEM) to solve boundary value problems of linear elastic solids, including brittle cracks. Higher order PDS defines an approximation fd(x) of a function f(x), defined over domain Ω, as the union of local polynomial approximation of f(x) over each Voronoi tessellation elements of Ω. The support of the local polynomial bases being confined to the domain of each Voronoi element, fd(x) consists of discontinuities along each Voronoi boundaries. Considering local polynomial approximations over elements of Delaunay tessellation, PDS define bounded derivatives for this discontinuous fd(x). Utilizing the inherent discontinuities in fd(x), PDS-FEM proposes a numerically efficient treatment for modeling cracks. This novel use of local polynomial approximations in FEM is verified with a set of linear elastic problems, including mode-I crack tip stress field

Tsunami Analysis Method with High-Fidelity Crustal Structure and Geometry Model

Higher fidelity seafloor topography and crustal structure models have become available with accumulation of observation data. Previous studies have shown that the consideration of such high-fidelity models produces significant effects, in some cases, on crustal deformation results that are used as inputs for tsunami analysis. However, it is difficult to apply high-fidelity model of crustal deformation computations to tsunami computations because of large computational costs. In this paper, we propose a new crustal deformation computation method for estimating inputs for tsunami computations, which is based on a finite element analysis method with remarkable reduction of computation costs by efficient use of the arithmetic space and the solution space. This finite element analysis method enables us to conduct 102−3-times crustal deformation computations using high-fidelity models with a degree of freedom on the order of 108 for the 2011 Tohoku earthquake example. Tsunami computations with typical settings are conducted as an application example to present the advantages and characteristics of the proposed method. Comparisons between results of the proposed and the conventional method reveal that large shallow fault slip around the trench axis may lead to significant differences in tsunami waveforms and inundation height distributions in some cases

Silenced Expression of NFKBIA in Lung Adenocarcinoma Patients with a Never-smoking History

Nuclear factor of κ-light polypeptide gene enhancer in B cells inhibitor α (NFKBIA), which is a tumor suppressor gene, was found to be silenced in lung adenocarcinomas. We examined NFKBIA expression, mutations in the EGFR and K-ras genes, and EML4-ALK fusion in 101 resected lung adenocarcinoma samples from never-smokers. NFKBIA expression was evaluated using immunohistochemistry. NFKBIA expression was negative in 16 of the 101 samples (15.8%). EGFR and K-ras mutations and EML4-ALK fusion were detected in 61 (60.5%), 1 (1.0%), and 2 (2.0%) of the 101 samples, respectively, in a completely mutually exclusive manner. Negative NFKBIA expression was observed significantly more frequently among the tumors with none of the three genetic alterations compared to those with such alterations (p＝0.009). In addition, negative NFKBIA expression was significantly more frequent among the EGFR-wild type samples compared to the EGFR-mutant samples (p＝0.013). In conclusion, NFKBIA expression was silenced in adenocarcinomas without EGFR/K-ras mutations or EML4-ALK fusion, suggesting that the silencing of NFKBIA may play an important role in the carcinogenesis of adenocarcinomas independent of EGFR/K-ras mutations or EML4-ALK fusion

Numerical Verification Criteria for Coseismic and Postseismic Crustal Deformation Analysis with Large-scale High-fidelity Model

Numerical verification of postseismic crustal deformation analysis, computed using a large-scale finite element simulation, was carried out, by proposing new criteria that consider the characteristics of the target phenomenon. Specifically, pointwise displacement was used in the verification. In addition, the accuracy of the numerical solution was explicitly shown by considering the observation error of the data used for validation. The computational resource required for each analysis implies that high- performance computing techniques are necessary to obtain a verified numerical solution of crustal de- formation analysis for the Japanese Islands. Such verification in crustal deformation simulations should take on greater importance in the future, since continuous improvement in the quality and quantity of crustal deformation data is expected

統合地震シミュレーション : 強震動と構造物地震応答の評価

Advances in computer technology and sciences enable us to carry out large-scale numerical simulations. As one of such, the authors have been simulating the entire process of an earthquake, i.e., generation and propagation of an earthquake, responses of structures and damage, and actions by people and communities for earthquake damage. This is an integrated earthquake simulation (IES). With the aid of the latest geographical information system (GIS), IES can automatically construct a computer model of a city of some hundred meters in scale. This paper presents the current state of IES, focusing on the simulation of strong ground motions and structure responses ; the structure response simulation applies several numerical analysis methods. Data exchanges between each method and IES are controlled by an interpreter program. The usefulness of IES is discussed. It is pointed out that IES provides vital information to form a common recognition of possible earthquake hazards and disasters by government offcials and residents

Prognostic impact of cancer stem cell-related markers in non-small cell lung cancer patients treated with induction chemoradiotherapy

The expression of several cancer stem cell (CSC)-related markers has been confirmed in non-small cell lung cancer (NSCLC). The aim of this study was to clarify the clinical role of CSC-related markers in patients with NSCLC undergoing induction chemoradiotherapy (CRT). Fifty patients with clinically diagnosed N2 or N3 NSCLC who underwent induction CRT with docetaxel and cisplatin concurrently with thoracic radiation followed by surgery were examined in this study. The expressions of CSC related markers (CD133, ALDH1, ABCG2, and Bmi-1) were examined using immunohistochemical staining in surgically resected specimens. Among the 50 patients, 20 patients had no residual tumor cells in the resected specimen when examined pathologically; CSC-related marker expressions and their correlation to survival were evaluated in the other 30 patients. After a median follow-up period of 72 months, the 5-year overall survival rate of the patients with CD133-positive or ALDH1-positive specimens was significantly worse than that of the patients with both CD133-negative and ALDH1-negative expressions (449% vs. 90.0%, respectively; P=0.042). In a multivariate analysis. CD133 and ALDH1 negativity (P=0.047) and cN2-3 single station metastasis (P=0.03) were significant independent prognostic factors for prolonged survival. The expressions of CSC-related markers after CRT were significantly correlated with a poor prognosis in patients with NSCLC. The development of therapeutic strategies including adjuvant therapy that take CSC-related marker positivity into consideration is likely to be a key factor in further improvements of the prognosis of patients undergoing trimodality therapy

Impact of GLUT1 and Ki-67 expression on early-stage lung adenocarcinoma diagnosed according to a new international multidisciplinary classification

High expression levels of glucose transporter isoform 1 (GLUT1) and Ki-67 are reportedly associated with malignancy-related clinicopathological factors in malignant tumors. Recently, a new histological IASLC/ATS/ERS classification for lung adenocarcinoma was proposed. In this study, we investigated the clinicopathological impact of GLUT1 and Ki-67 expression on early-stage lung adenocarcinoma classified according to the IASLC/ATS/ERS classification. One hundred and five patients with completely resected stage IA lung adenocarcinoma were retrospectively classified into two groups, a 'non-invasive type' (n=31) or an 'invasive type' (n=74), based on the IASLC/ATS/ERS classification. GLUT1 and Ki-67 expression status was evaluated using immunohistochemistry. The epidermal growth factor receptor (EGFR) and KRAS mutation status was determined using PCR-based assays. Positive GLUT1 and Ki-67 expression and EGFR and KRAS mutations were detected in 28 (27%), 33 (31%), 51 (49%) and 5 (8%) cases, respectively. Positive GLUT1 expression was significantly associated with a wild-type EGFR and mutant KRAS status. A multivariate analysis revealed that positive GLUT1 expression was independently associated with the 'invasive type'. In multivariate analyses for overall survival (OS) and disease-free survival (DFS), positive Ki-67 and GLUT1 expression was the only independent factor for a poor OS (P=0.012) and DFS (P=0.040), respectively. In addition, when stratified according to the GLUT1 and Ki-67 status, double-positive cases had the poorest DFS and OS times, compared with the other categories. Positive GLUT1 expression is associated with the invasive character of early-stage lung adenocarcinoma and with early disease relapse. Our results strongly suggest that GLUT1 and Ki-67 play important roles in acquiring biological malignant potential in early-stage lung adenocarcinoma