Tim Ahern

Data Products at the IRIS DMC: Stepping Stones for Research and Other Applications

In 2010, the Incorporated Research Institutions for Seismology (IRIS) Data Management Center (DMC) expanded the preexisting effort to generate, archive, and distribute data products derived from the extensive data archives of the center, which include the IRIS Program for Array Seismic Studies of the Continental Lithosphere (PASSCAL), Global Seismographic Network (GSN), EarthScope, and many other data sources. This expansion included dedicating two new full‐time staff to data products and to the development of a new system to manage and distribute them. With community guidance provided by a data products working group (DPWG), DMC has developed a number of freely available unique and increasingly popular data products for the seismological community. In addition, DMC is also archiving and distributing other data products that are produced by community members. A complete list of data products managed by DMC is maintained here: http://www.iris.edu/dms/products. Many of these are available from the Searchable Product Depository (SPUD, http://www.iris.edu/spud), the DMC data product management system. Traditionally, data products result from specialized processing applied during research by the principal investigators and their teams. Products span the range of simple plots or animations derived from waveform data to highly refined models. Some waveform‐processing techniques (e.g., receiver functions) have gained wide community use and can be derived by widely accepted algorithms. Such first‐order data products make ideal candidates for routine generation to provide a standard for the user community. Data products are typically derived from raw data to serve as insightful summaries of the raw time series data, or as quality control metrics, or as foundations or stepping stones to more specialized products and research. The overall goal of the DMC data product effort is to produce and manage a variety of community‐approved and utilized data products that complement the raw data managed at the DMC and ultimately serve …

Accessing a multi-terabyte seismological archive using a metadata portal

Seismological data are voluminous. Typical researchers cannot be expected to be able to search through the quantity of seismograms to find those that might contribute to their research topic. For this reason, metadata, stored in a relational database management system is used to assist seismologists in determining which pieces of the seismological archive may possess the information needed for their research topic.

Expanding the Global Seismographic Network

Seismology is an inherently global science. While the devastating effects of large earthquakes are limited to the immediate epicentral area, the seismic waves produced by even moderate earthquakes are recorded world wide and can be used to probe the Earth’s deep interior and provide information on the structure and dynamics of our evolving planet. In turn, the recording of seismic waves globally can be used to locate and quantify the nature of earthquake sources. A cornerstone of global seismological research has been a long and productive tradition of international cooperation in the collection and exchange of seismographic data.

Exploiting the global Internet for distribution of global seismological data

The Incorporated Research Institutions for Seismology (IRIS) is a university consortium of 85 US universities and 19 research institutions that are either United States or Foreign Affiliates of IRIS. IRIS is a non-profit corporation but receives its primary funding from the National Science Foundation and the Air Force Office of Scientific Research. IRIS consists of three core programs. The Global Seismic Network (GSN) has as its goal the installation and operation of approximately 128 continuously recording seismic observatories recording the three dimensional seismic wavefield in the frequency band from several thousand seconds to a few hertz (5). Some stations also record higher frequencies up to 100 samples per second using additional sets of seismometers with appropriate pass bands. IRIS GSN stations record data continuously normally at 20 samples/second or sometimes 40 samples/second. The Program for Array Seismic Studies of the Continental Lithosphere (PASSCAL) had as its goal the acquisition of 6000 channels of recording capability in a small, portable, and flexible system. PASSCAL experiments vary from conventional oil industry type acquisition projects, longer offset refraction studies, and a new class of broadband recording of passive source experiments in a variety of international locations. The third component of IRIS is the Data Management System (DMS) The IRIS DMS is responsible for the quality control, archiving, data basing and distribution of data from the GSN and PASSCAL as well as several other organizations that contribute data to the DMS. The heart of the IRIS DMS is the Data Management Center (DMC) in Seattle, Washington. The INTERNET was originally a tool used primarily by government laboratories and research institutions including US universities. Coming from this environment the IRIS DMS has exploited the INTERNET as a method for distributing large amounts of seismic data, software, and other information for nearly a decade. This presentation will detail some of the methods of INTERNET use that IRIS has been involved in.

Finding needles in haystacks

The Incorporated Research Institutions for Seismology (IRIS) is a consortium of the roughly 90 universities in the United States with research programs in seismology. However, many other organizations, within and outside the U.S., are affiliated with IRIS.