ACADEMIA

UT's Center for Space Research and Texas Advanced Computing Center
enable real-time decision-making for scientists and first responders

The magnitude 7.0 earthquake that rocked Haiti on January 12 unleashed the greatest natural disaster in the history of the Western hemisphere. The quake and subsequent aftershocks leveled buildings throughout the capital of Port-au-Prince, leaving over one hundred thousand dead, as many as a million without shelter, and much of the country in ruins.

In the days that followed the earthquake, first responders arrived in Haiti to distribute aid and medical relief and to assist in the search and rescue effort, locating people in the wreckage and bringing them to safety.

These efforts, however, wouldn’t have been as well-coordinated and successful without the use of accurate satellite and aerial imagery of the kind provided by the Center for Space Research (CSR) at The University of Texas at Austin. CSR, through its Mid-American Geospatial Information Center (MAGIC), is the repository of remote sensing data drawn from a variety of sources. The MAGIC team collects this imagery and uses geospatial analysis to provide support for disaster response by affording access to vital information.

“We know the typical suite of products that responders need in the field and have been developing those using satellite imagery, and more recently, aerial imagery,” said Gordon Wells, program manager and principal investigator for MAGIC.

In Haiti, MAGIC has served as one of the main conduits in the flow of information — satellite, aerial, and radar imagery, and elevation data from photographic, LiDAR and radar sensors — to help emergency operations in the region. Working with the Texas Advanced Computing Center (TACC) since the start of the disaster, they have produced, organized, and distributed this data to scientists and responders in a timely and useful fashion, while leading a charge to create better geospatial information for the region.

“This is the information that you need to assess risk throughout the region,” Wells said. “It gives you a foundation upon which you can develop plans to assist the reentry and recovery of the entire region that has been impacted.“

The process of getting information to responders isn’t simply a question of delivering data. Satellite images captured obliquely from space distort the Earth’s topography such that the raw image files from satellites are often inaccurate, limiting their usefulness. This was the case with the original images used by rescue workers in Haiti.

“If you were out in the field and you had a GPS unit to keep track of where you had visited to do a search and clear operation, you could be blocks off in your geo-location with respect to an uncorrected image-map,” Wells said. “We’re refining the geospatial data so that the field teams can use the imagery effectively during their field traverses.”

This process, called geospatial image registration, integrates different sets of data to produce image products having a more accurate reference system synchronized with map coordinates. Registration is necessary to be able to precisely pinpoint locations.

Within three days of the earthquake, CSR scientists were able to register the initial data sets, combining satellite data with geodetic survey points collected by ground-based GPS readings, and post the finished products to data servers for retrieval by first responders.

“Corrected satellite imagery is being published to the National Geospatial-Intelligence Agency site that many of the responders are using now, and that’s being passed over to Google,” said Wells. “People focus on the best available data, and that’s the data that has been corrected and validated.”

Research Enablers

Wells and his colleagues are also playing a key role assisting the research teams that are investigating the nature of the earthquake, and the likelihood (and possible location) of future seismic activity.

The CSR team has been working closely with Paul Mann from The University of Texas at Austin’s Institute for Geophysics, and Eric Calais from Purdue University’s Department of Earth and Atmospheric Sciences, who have both studied the geology and earthquake history of Haiti and the Dominican Republic for decades. They published the definitive studies on the fault systems and seismicity of Haiti, including, prophetically, a 2008 report that forecast a quake on the Enriquillo fault — which is what occurred on Jan. 12, 2010.

Both researchers are currently in Haiti to examine the visible evidence of the fault rupture and to determine what risks remain for future earthquakes as stress fields readjust across the region.

While Calais reoccupies his previous geodetic survey sites and sets up high-order GPS gear to collect information to compare with his baseline data, Mann is making his way towards the epicentral region to see precisely where the rupture occurred, and to measure the lateral offset of the fault. They will combine their findings to assess how much of the fault ruptured and where the strain has been repositioned.

One of CSR’s major roles, since the researchers’ arrival, has been to use both satellite imagery and low altitude aerial photography to provide an accurate image base for Mann’s survey of the rupture, and to ascertain which of Calais’ sites located on building rooftops survived the earthquake. Preliminary modeling indicates that the fault may still be locked in the Port-au-Prince region, increasing the likelihood of a future quake.

“We’ve got several thousand ground-troops in Haiti and over a million Haitians who have no place to live. Everyone needs to know what the potential is in the immediate future for a quake of the same magnitude, or a quake of lesser magnitude closer to Port-au-Prince,” Wells said.

CSR is also working with NASA’s Jet Propulsion Lab (JPL) to conduct a series of flights with an interferometric radar system to investigate the entire length of the Enriquillo Fault. The first JPL aircraft mission occurred on January 27, and the fault will be re-imaged by the same sensor over the next two weeks to detect ground motion. In the coming weeks, CSR will also be supporting the work of UT Engineering professor, Ellen Rathje, who will be conducting structural surveys of building damage to figure out what the ground shake characteristics were in Port-au-Prince.

Cyberinfrastructure to the Rescue

Just as researchers and first responders in the field count on the Center for Space Research for crucial information, CSR depends on the Texas Advanced Computing Center for the cyberinfrastructure, information technology, and computing expertise that allows them to store and organize the enormous amounts of collected data, and serve it remotely to the researchers and emergency workers who need it.

“We always rely on TACC for the means to access these very intense, very large data sets that have to be manipulated quickly and in an organized way, so we can grab the right piece of information that we need from the terabytes of data that flow in from sensor systems, both orbital and airborne,” said Wells.

TACC’s role has been on the backend of the technology, providing storage, high-speed data transfer, and web hosting for CSR’s diverse research projects. In emergency situations like the earthquake in Haiti, the value of these supercomputing assets quickly becomes apparent.

“We don’t know immediately which piece of data is going to be the most useful because of the fluid situation in the field,” said Wells. “As people are displaced out of Port-au-Prince, they’re resettled in other areas that we haven’t studied with the intensity that we have around the primary damaged area. We have to go back and revisit data, and collaborating with TACC allows us to do that with speed and efficiency.”

TACC’s premier data resource, Corral, was built with this kind of dynamic, data-driven computing in mind. Deployed in April 2009, Corral consists of 1.2 Petabytes of online disk and several servers providing high-performance storage for all types of digital data. TACC consulted with CSR in the planning stages of the system to ensure Corral was capable of the rapid organization and retrieval of massive data sets required for the real-time decision-making required in situations like these. Because of the strong relationship between the centers, Corral needed very little lead-time before it was ready to act as a functional portal for CSR’s geospatial Haiti data.

“It’s what Corral is designed to do,” said Chris Jordan, the senior operating systems specialist responsible for data infrastructure at TACC. ”The idea is that you have, effectively, unlimited storage that can be very flexibly allocated and actually can serve multiple purposes at the same time.”

Jordan believes that now that this sophisticated infrastructure is in place, what needs to be done is to make the technology, and the massive amount of available information, useful to those in the field.

As the Center for Space Research receives new data — from NASA jets creating interferometric radar maps of the fault structure to 15 cm. color aerial imagery where you can see individual people — the MAGIC team will continue to prepare those files for use in Haiti, improving the information available to people on the ground.

“There are probably many instances where you can point specifically to lives that have been saved, but I would also say, more generally, that it helps to preserve the life and property of the citizens in that region,” said Wells. “If you were to attempt this relief effort without any of this information, your horizon of knowledge would be so limited.”