UTIG Provides Seismic Data to the World

During the last several years Senior Scientist Tom Shipley and others at The University of Texas Institute for Geophysics (UTIG) have developed the Marine Seismic Data Center to support long-term access and archiving of seismic data. The Academic Seismic Portal (ASP) at UTIG serves up these and other data acquired on marine geology and geophysics cruises. Web access provides the public a unique opportunity to look beneath the world's ocean floor. Access to the ASP is through UTIG's website.

Marine geophysicists use sound waves to image sediments and other rock types that lie beneath the sea floor. During field campaigns research vessels tow long cables, called streamers, and air guns, which put out large blasts of pressurized air into the water. Sound waves created by the air blasts penetrate and bounce off different rock layers at and below the sea floor. Returning sound waves are detected by special microphones encapsulated in the streamers. Squiggly lines that correspond to the sound waves' recorded travel times are then plotted. Stand back from the squiggles and you'll see an image of Earth's subsurface reminiscent of a road cut.

The ASP now makes these 'squiggle plots' accessible to the public, who can download images and metadata for cruises in the ASP's database. Current data holdings include an impressive list of academic cruises from the Gulf of Mexico, the Caribbean Sea, the west coast of Central America, Pacific and Atlantic Oceans, the east coast of Africa, the Arctic, and Antarctica.

The public can search the database using a map-based tool, which conveniently displays current data holdings on a world map, or they can search the ASP archives using a cruise name, data type, or by access restrictions. For people unfamiliar with the nuances of seismic image processing and primarily concerned with obtaining an attractive image, ready-made images are available. For more advanced users, the ASP offers a tool that permits user-controlled image processing.

To date, the ASP archives 5TB of data for 250 cruises with 32,000 primary data files involving more than 30 institutions. Academic cruises often represent years of focused study culminating in publications and student theses so scientists often become very attached to their study areas.

"We find that sometimes scientists are reluctant to contribute data to the database", says Lisa Gahagan, who handles data intake for the site. "We reassure them by giving them the power to decide on access restrictions for the data they give us."

Shipley also encourages marine geoscientists to contribute data to the ASP archives as a way to satisfy grant requirements outlined by the National Science Foundation (NSF), the primary funding institution for academic cruises.

"NSF requires scientists to make their data available to the public two years after a cruise or at the end of the grant. The ASP provides scientists an easy way of fulfilling this obligation. Major objectives [for the ASP] are to make the contribution process easy and efficient and to acknowledge the contributor as the data source", says Shipley.

Following data contribution, scientists are informed about their data's popularity. The originating data provider is notified when their data are downloaded or requested from the ASP.

More than 1500 users are currently registered and have downloaded over 90,000 primary data files, images and navigation. Over 84 countries are represented with about 35% of those registered from the U.S.

Most people request and download data primarily for course materials and student projects, but a significant amount use these data for academic research, academic software development and testing, commercial activities, and for general curiosity.

The ASP project is supported by funds from the National Science Foundation (OCE-0826282) as part of a cooperative project with Lamont-Doherty Earth Observatory and by the Institute for Geophysics at The University of Texas at Austin.

-Marcy Davis