The QuakeSim interdisciplinary research team has developed a federated database system, which records and provides portal-based access to a variety of geoscientific information important to the earthquake study and forecasting process.
This includes fault, seismicity, and other information key to modeling earthquakes and tsunamis. Through the QuakeSim portal, scientists can discover relevant information, and access, visualize, and import data to simulation programs and other codes.
This is accomplished by utilizing an inter-connected (federated) set of ontologies to describe the semantics of the information and the inter-relationships among the data. Data are recorded in source form with error estimates included, are geotagged as appropriate to specify precisely where on the globe the data were obtained, and are converted as necessary for use by scientists.
Data is delivered by the use of a suite of Web Services tied to the semantic metadata (ontology) specifications. A primary goal of the QuakeTables federated database is to provide an integrated resource for simulation and modeling software, such as GeoFest and Virtual California.
A key feature of QuakeTables is to allow for multiple fault interpretations, which can be tested in the models and simulations. As such, QuakeTables does not define a standard set of faults, but allows users to select faults from standard sets, from research publications, or from user-defined attributes. At present, the system is being enhanced to include GPS and InSAR data.
QuakeSim is framework to modeling, simulating and understanding earthquake and tectonic processes. QuakeSim focuses on modeling the interseismic process through various boundary element, finite element, and analytic applications, which run on various platforms including desktop and high end computers. QuakeSim gets its data from various online databases, web services and web feature services. These data sources are hosted in different locations on various platform all being accessible through the QuakeSim portal. QuakeTables is an ontology-based federate set of databases for fault, GPS and GPS time series data. QuakeSim uses QuakeTables to store, retrieve and access its data. Real time data support is provided through publish/subscribe infrastructure and RDAHMM support.
The earthquake prediction process is illustrated in the following diagram [Figure 1]:
Figure 1. QuakeSim earthquake prediction process
The geoscientific data used and produced by QuakeSim is of a heterogeneous nature. Since the target data is published using different data types, assumptions, error estimates and units. Furthermore, once the data is processed by simulation packages a new set of processed data is produced (with a different set of data types) and needs to be stored. Individual data sets are stored independently in federated databases along with its meta data. A local ontology processor takes care of pushing the data to the respective individual databases and retrieving it using a unified representation. This representation includes: data items, their data types and geophysical definitions (e.g. width, in kilometers, the specifications of the two end points the width is measured in between). This fault data specification will be used by simulation and modeling software like GeoFest and Simplex. Within this effort mathematical relationships between fault date items were defined to ensure the consistency and semantic integrity of the data. Figure 2 shows the architecture of QuakeTables.
Figure 2: QuakeTables Architecture
To maintain compatibility between QuakeSim modeling and simulation packages, there are two types of data sets available in QuakeTables. First, QuakeTables DataSet (QT DataSet) which is a standard data type pre-defined in QuakeSim. QT DataSets are used by modeling and simulation software directly dealing with the QuakeTables API like GeoFest and Simplex. Second, to represent data that does not have a pre-defined format known to QuakeTables we use a generic DataSet which could represent data taken directly from publications or results/intermediate results of simulations that do not conform to a QT DataSet. All these DataSets are linked to each other and can be cited from one another. Figure 3 shows a sample relationship between such DataSets.
All of QuakeSim's features are accessible through the QuakeSim Portal. The newly designed portal provides users with the ability to perform queries using QuakeTables or real time data, run simulations and view results of previously run simulations. Figure 4 is a snapshot of the QuakeSim portal used to display real time GPS time series data on GoogleMaps.
Figure 3. QuakeTables Data Sets
Figure 4. QuakeSim Ports @ http://quakesim.org
QuakeTables has support for earthquake fault data, GPS and GPS time series data. Efforts are made to include interferograms processed from Interferometric Synthetic Aperture Radar (InSAR) data. This will enable QuakeSim to process data from future InSAR missions like the planned NASA Dynamics, Ecosystem Structure, and Dynamics of Ice (DESDynI) mission.