Vol.9 No.2 2016

Research paper−99−Synthesiology - English edition Vol.9 No.2 pp.99–111 (Sep. 2016) of future mega-earthquakes by clarifying the occurrence period and scale of past mega-earthquakes by studying the past activity (the activity history) of active faults and tsunami deposits.[4][5] Other studies being conducted at AIST aim to swiftly detect abnormalities in observations obtained by constant monitoring of crustal changes (minute movements and changes near the Earth's surface) and earthquake occurrences in the Japanese islands using the latest observation technology.[6] The objective of this study was to clarify earthquake occurrence mechanisms and underground rock behavior, because it is impossible to understand how earthquakes occur unless these are clarified. This study is an attempt to refine the earthquake forecast model by clarifying earthquake occurrence models and scenarios. Figure 1 is a flow chart that summarizes the various components of research that contribute to earthquake forecasting and shows the role and position of high-temperature and high-pressure rock experiments in the overall research scheme.[7][8] In this paper, I report experimental technologies and methods used to accelerate geological phenomena that normally progress on a thousand-year timescale in a laboratory, and I show how rock experiments conducted with those technologies and methods can be used to verify an earthquake forecast model.An earthquake occurs when a fault moves beneath the earth’s surface. When a rock fractures underground, the fracture is accompanied by rapid movement (displacement) along a certain plane (the fault plane). Although in the natural world, an earthquake is a complex phenomenon, rock experiments have an important role in determining the dominant factors 1 IntroductionWe, the members of the earthquake research community, wish to contribute to making society resilient to disasters. The final goal of the study of earthquakes is to help mitigate disasters caused by earthquakes through scientific results. Although disasters cannot be prevented, society can prepare appropriately for them. When information and forecasts that are accurate and geologically and physically reliable are quickly transmitted, they become basic information useful to society to prepare for disasters. Forecasts must be delivered not as mere hypotheses; rather, they must be based on verified results and delivered in the words of science. Although uncertainty is inherent in earthquake forecasts arising from data and models,[1] the AIST research team aims to improve earthquake forecasts by building an earthquake forecast model with high precision. To construct a highly precise earthquake occurrence model, it is necessary to first develop a geologically and physically reliable model of the various processes that must take place for an earthquake to occur. In this paper, I report techniques and methods developed to verify such a model.In overview, earthquake research includes various research methods, such as geological surveys, observations of phenomena such as seismic waves and groundwater, computer simulations, and laboratory experiments. All of these various types of earthquake studies supplement each other to help us better understand earthquakes.[2][3] For example, research is being conducted to forecast the occurrence period and scale - Evaluation of long-term geological processes by a compressed timescale process model-The reliability of earthquake forecast information is important for disaster mitigation in our society. A physical model of the earthquake generation process was constructed to improve the reliability of earthquake forecast information. We proposed a model based on the information extracted from geological surveys. Our model was evaluated using experimental techniques in the laboratory. During the experimental study, we considered two disparities between laboratory and natural conditions, which were differences in environmental conditions and timescale. A new experimental rock deformation technique was developed that unifies previous and newly developed techniques. Long-term geological processes were evaluated by a process model operating over a compressed timescale.Development of rock deformation techniques under high-pressure and high-temperature conditionsKeywords : Earthquake, geological survey, rock mechanics, high-temperature and high-pressure, disaster mitigation [Translation from Synthesiology, Vol.9, No.2, p.97–107 (2016)]Koji MasudaResearch Institute of Earthquake and Volcano Geology, AIST Tsukuba Central 7, 1-1-1 Higashi, Tsukuba 305-8567, Japan E-mail: Original manuscript received January 29, 2016, Revisions received March 11, 2016, Accepted March 12, 2016


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