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Large earthquakes are catastrophic natural disasters which can potentially cause massive casulaties and huge property loss. In the beginning of the new century, large earthquakes violently struck the world, especially in the Asia-Pacific region. Nearly 300,000 people were killed by the magnitude 9.0 Northern Sumatra Earthquake and tsunami, and the magnitude 7.8 Pakistan earthquake of October 8th, 2005, which resulted in 90,000 deaths. In the meantime, there has been great progress in computational earthquake physics. New understanding of earthquake processes, numerous ideas on earthquake dynamics and complexity, next-generation numerical models and methods, higher performance supercomputers, and new data and analysis methods are emerging. These include the SERVO gird and iSERVO, LSM (Lattice Solid particle simulation Model); Australian Computational Earth Systems Simulator (ACcESS); Japan’s Earth Simulator; GeoFEM; GeoFEST; QuakeSim; LURR (Load-Unload Response Ratio); earthquake Critical Point Hypothesis, PI (Pattern Informatics), Critical Sensitivity, friction laws and seismicity, episodic tremor, the Virtual California model, interaction between faults and the interactions between earthquakes, ROC (Receiver Operating Characteristic), SMDM (Statistical Mesoscopic Damage Mechanics) and MFEM (Multi-scale Finite-Element Model), among others.

We are developing simulation and analysis tools in order to develop a solid Earth Science framework for understanding and studying active tectonic and earthquake processes. The goal of QuakeSim and its extension, the Solid Earth Research Virtual Observatory (SERVO), is to study the physics of earthquakes using state-of-the-art modeling, data manipulation, and pattern recognition technologies. We are developing clearly defined accessible data formats and code protocols as inputs to simulations, which are adapted to high-performance computers. The solid Earth system is extremely complex and nonlinear, resulting in computationally intensive problems with millions of unknowns. With these tools it will be possible to construct the more complex models and simulations necessary to develop hazard assessment systems critical for reducing future losses from major earthquakes. We are using Web (Grid) service technology to demonstrate the assimilation of multiple distributed data sources (a typical data grid problem) into a major parallel high-performance computing earthquake forecasting code. Such a linkage of Geoinformatics with Geocomplexity demonstrates the value of the Solid Earth Research Virtual Observatory (SERVO) Grid concept, and advances Grid technology by building the first real-time large-scale data assimilation grid.

We describe the goals and initial implementation of the International Solid Earth Virtual Observatory (iSERVO). This system is built using a Web Services approach to Grid computing infrastructure and is accessed via a component-based Web portal user interface. We describe our implementations of services used by this system, including Geographical Information System (GIS)-based data grid services for accessing remote data repositories and job management services for controlling multiple execution steps. iSERVO is an example of a larger trend to build globally scalable scientific computing infrastructures using the Service Oriented Architecture approach. Adoption of this approach raises a number of research challenges in millisecond-latency message systems suitable for internet-enabled scientific applications. We review our research in these areas.

The foster ongoing international cooperation beyond ACES (APEC Cooperation for Earthquake Simulation) on the simulation of solid earth phenomena, agreement was reached to work towards establishment of a frontier international research institute for simulating the solid earth: iSERVO =International Solid Earth Research Virtual Observatory institute (http://www.iservo.edu.au). This paper outlines a key Australian contribution towards the iSERVO institute seed project, this is the construction of: (1) a typical intraplate fault system model using practical fault system data of South Australia (i.e., SA interacting fault model), which includes data management and editing, geometrical modeling and mesh generation; and (2) a finite-element based software tool, which is built on our longterm and ongoing effort to develop the R-minimum strategy based finite-element computational algorithm and software tool for modelling three-dimensional nonlinear frictional contact behavior between multiple deformable bodies with the arbitrarily-shaped contact element strategy. A numerical simulation of the SA fault system is carried out using this software tool to demonstrate its capability and our efforts towards seeding the iSERVO Institute.

Seismogenic process is a nonlinear and irreversible one, so that the response to loading of a seismogenic zone is different from the unloading one. This difference reflects quantitatively the process of an earthquake preparation. A physics-based new parameter-Load/Unload Response Ratio (LURR) was proposed to measure quantitatively the proximity to a strong earthquake and then used to be an earthquake predictor. In the present paper, a brief history of LURR is recalled; inspection of real earthquake cases, numerical simulations and laboratory studies of LURR, prediction efforts in terms of LURR, probability problem of LURR and its prospect are also expatiated.

The spatial and temporal variation of LURR (Load/Unload Respond Ratio) in California during April 2002 to June 2004 was studied in this paper. The result shows that before the San Simeon earthquake (35.7 N, 121.1 W) on Dec. 22, 2003, anomalous region occurred successively near the epicenter from April 2002 to June 2002, and the maximum anomaly of occurred in May, 2002. The published research work pointed out that the anomaly near the San Simeon earthquake appeared from March, 2002. Compared with the five earthquake cases out of the six with M≥6.5 in California during the period from 1980 to 2001, the maximum and duration of anomaly before this earthquake are among the normal ranges, but the time delay from the maximum anomaly time to the occurrence time of this earthquake is the longest one. The result also shows that two areas with anomalies occurred from Oct. 2002 and Dec. 2002, respectively. According to statistical characteristics of the relationship between anomalies and the coming earthquakes, the seismic tendency in California was discussed in this paper.

In terms of the spatial scanning of LURR (Load-Unload Response Ratio), we have been predicting the seismic tendency within the next year for the mainland of China from 1995 to 2003. In order to make the quantitative retrospective assessment of LURR method, we compare the results with Poisson null hypothesis. The results show that the prediction by LURR method is much better than Poisson hypothesis.

After reviewing the problems associated with the current implementation of the LURR theory, we suggest that taking account of stress field complexity and stress reorientation may resolve these problems. By introducing the concept of Maximum Faulting Orientation (MFO), we propose a new approach for calculating LURR. Results presented for the case of the Northridge earthquake provide encouragement for the stress-reorientation explanation and the new approach.

The Load/Unload Response Ratio (LURR) method is a proposed technique to predict earthquakes that was first put forward by (). LURR is based on the idea that when an area enters the damage regime, the rate of seismic activity during loading of the tidal cycle increases relative to the rate of seismic activity during unloading in the months to one year preceding a large earthquake. Since earth tides generally contribute the largest temporal variations in crustal stress, it seems plausible that earth tides would trigger earthquakes in areas that are close to failure (e.g., . However, the vast majority of studies have shown that earth tides do not trigger earthquakes (e.g., ; ; . In this study, we conduct an independent test of the LURR method, since there would be important scientific and social implications if it were proven to be a robust method of earthquake prediction. () undertook a similar study and found no evidence that there was predictive significance to the LURR method. We have repeated calculations of LURR for the Northridge earthquake in California, following both the parameters of (personal communication) and the somewhat different ones of (). Though we have followed both sets of parameters closely, we have been unable to reproduce either set of results. Our examinations have shown that the LURR method is very sensitive to certain parameters. Thus it seems likely that the discrepancies between our results and those of previous studies are due to unaccounted for differences in the calculation parameters. A general agreement was made at the 2004 ACES Workshop in China between research groups studying LURR to work cooperatively to resolve the differences in methods and results, and thus permit more definitive conclusions on the potential usefulness of the LURR method in earthquake prediction.

A series of acoustic emission (AE) experiments of rock failure have been conducted under cyclic load in tri-axial stress tests. To simulate the hypocenter condition the specimens are loaded by the combined action of a constant stress, intended to simulate the tectonic loading, and a small sinusoidal disturbance stress, analogous to the Earth tide induced by the Sun and the Moon. Each acoustic emission signal can indicate the occurrence time, location and relative magnitude of the damage (micro-crack) in the specimen. The experimental results verified some precursors such as LURR (Load/Unload Response Ratio) and AER (Accelerating Energy Release) before macro-fracture of the samples. A new parameter, the correlation between the AE and the load, has been proposed to describe the loading history. On the eve of some strong earthquakes the correlation between the Benioff strain and the Coulomb failure stress (CFS) decreases, similar to the variation of LURR prior to strong earth quakes.