Spring  >>  2004  

Geospatial Technology & World Threats

Modeling of disaster scenarios in several American cities

Dexter Ingram
Professional Staff Member
House Select Committee on Homeland Security
Washington, DC

Joe Ingram
Senior GIS Consultant
Ingram Engineering Inc.
Brookeville, Md

Whether during a terrorist attack or a natural disaster, the ability of the public and private sectors to react effectively depends substantially on how well they have planned their response strategies. To plan such responses requires an understanding of a variety of attack scenarios. Spatial technologies are instrumental for threat assessment.

During the past few years, state and federal legislators, their staffs, the media, first responders, and numerous other organizations have learned a great deal about terrorist threats. This education has been bolstered by such tools as satellite imagery and geographic information systems (GIS), which can be used to forecast and model potential hazardous events and the emergency response to those disasters.

Figure 1. In this scenario, a nuclear “suitcase bomb” explodes in downtown Houston, demolishing a nine-block radius, shown in red. Seventeen mile-per-hour winds blow the radioactive cloud east (the plume spreading toward the bottom of this page), with lethality diminishing as the plume travels.
For instance, using desktop or Web-based GIS, analysts can model the dispersion of a nuclear, radiological, biological, or chemical plume. Specialists can overlay these models onto a city map to examine how attacks would affect given areas and populations. Further layers such as satellite imagery can provide additional understanding, including topography and other information for remote locations. Threat-assessment advisers then can run various scenarios to plan optimal evacuation routes and determine where to place decontamination facilities and chemical/biological detectors.

Among some of the well-tested programs for visualizing these scenarios both at home and abroad are Consequence Assessment Tool Sets – Joint Assessment of Catastrophic Event (CATS-JACE or C-J) and Hazard Prediction and Assessment Capability (HPAC). Used primarily for domestic threat assessment because of its in-depth U.S. city-level data, C-J is a set of models that simulates both natural and manmade catastrophes, from earthquakes to chemical weapons attacks to hazardous material spills.

With a few extensions, C-J enables users to generate predictive models and conduct casualty and damage assessment. HPAC, similar to C-J but with more international data and a larger variety of unconventional threat scenarios, is more often used to model threats abroad. The two GIS computer models have proven invaluable for policy briefings, public education and event preparation during the past few years.

Modeling with Weather and Facilities
Developed by Science Applications International Corporation (SAIC) just after the first Gulf War, the Defense Threat Reduction Agency (DTRA) and the Federal Emergency Management Agency (FEMA) distributed C-J to support emergency managers’ training exercises, contingency planning, and logistical planning, as well as to calculate requirements for humanitarian aid and force protection. The GIS interface allows users to combine and manipulate multiple layers of information on a variety of visual information backgrounds and maps to assess affected persons, property and infrastructure. C-J can be used regardless of the user’s level of expertise or access to information. The technologies allow the modeling of scenarios based on current weapons technology and past results from biological, chemical and radiological experiments.

The models are based on data pulled from the DTRA database and combined with more than 150 other databases, including census, nuclear plants, military bases, ports and chemical processing plants. In addition, the new JACE program allows for an actual satellite image to overlay a traditional GIS street map theme. Commercial space remote sensing companies now can provide in-depth satellite imagery of buildings, which opens a new world of analysis. Currently, such firms can develop scenarios that assess structural damage to buildings and casualty estimates for those within.

The analysis becomes even more accurate when it links directly to the National Weather Service (NWS) and pulls regional weather for the time the simulated event takes place. This can involve either forecasted weather or, if the event is too far away for an accurate forecast, historical averages of weather over the past 20 years. The program then produces a map that shows the areas and populations affected and the level of lethality of the attack.

Homeland Security Scenarios
At the request of U.S. House and Senate staff--as well as media outlets such as The Houston Chronicle, Washington Times, York Daily Record, and The Times (London)--C-J was used to model a variety of scenarios involving several American cities. Specifically, simulations done included dirty bombs detonating in downtown areas; a crop duster spreading anthrax, sarin, botulinum toxin, or nerve gas over large populations; a nuclear reactor leak; a missile intercept; and a nuclear explosion. In Houston, the media used this model to challenge local government officials regarding their disaster-preparedness plans.

Following the first anniversary of Sept. 11, Mike Hedges of The Houston Chronicle interviewed local authorities and first responders to see if his city was prepared for the terrorist attacks modeled. He also asked local, state and federal officials to describe how they would respond to these scenarios. In a graphic front-page story, he described a nuclear bomb small enough to be hidden in a briefcase. It would level downtown Houston, flattening many of the 58 skyscrapers and killing up to 130,000 workers (see Figure 1).

This simulation included data from ESRI StreetMap, the National Weather Service (NWS) and the National Imagery Mapping Agency (NIMA), now called the National Geospatial Intelligence Agency (NGA). StreetMap contained the necessary detailed road information and map layers of downtown Houston. The C-J software ties to NWS's database to get the latest forecast information to determine the plume dispersion. Additional map layers (buildings, parks, water bodies, and so forth) came from NGA sources. All the data were plotted in a geodetic coordinate system (degrees latitude and longitude).

The simulation demonstrated the bomb exploding outside City Hall, destroying it, the Houston Police Department's headquarters, and the Harris County administrative offices. It would have killed most local leaders and law enforcement officials, crippling the city's ability to respond to the disaster. Based on the simulated weather data, the wind dragged the radioactive cloud through the East End and beyond the I-610 Loop, killing 10 percent of those in its stream and leaving thousands more ill.

Houston authorities had considered disaster scenarios in planning emergency responses, but the simulation and Hedges' article fostered debate about how prepared the city was for an attack. The discussion pointed out deficiencies for the city to address. Following Houston's lead, many other localities performed similar simulations to test their preparedness.

Attacks From Over the Border
Soon after Sept. 11, the Heritage Foundation Homeland Security Task Force used C-J to help assess port and border security threats. The analysis showed the U.S. is still vulnerable even if the attack doesn't start on U.S. soil. The group ran four nuclear and biological scenarios, looking at the border cities of Detroit, Michigan; San Diego, California; Buffalo, New York; and El Paso, Texas.

One of many mock border scenarios modeled a nuclear explosion in Mexico across the border from El Paso. After purchasing an old Soviet suitcase nuclear weapon in Central Asia, a terrorist smuggles it into Mexico to detonate it near the U.S. border. Traveling by car, the suicide bomber makes his way toward El Paso. South of the border, he pulls into a vehicle inspection station and detonates a 3-kiloton nuclear bomb, equivalent to 3,000 tons of dynamite. In this scenario, much of El Paso is devastated, even though the bomb exploded on the other side of the border. Prevailing winds blow radiation to San Antonio. Authorities do not know if this is a single attack or a precursor to other attacks. Fortunately it's just a simulation. But it does help to better prepare the local and federal authorities and first responders who would be involved in such a catastrophic attack.

Military Command and Control
As useful as the previously discussed models are, GIS software that enables battle management modeling is even more advanced. In addition to C-J and HPAC, the U.S. Air Force, for instance, uses its own command and control mapping software for its Theatre Battle Management Core Systems Unit Level (TBMCS-UL). This GIS software, deployed at Air Combat Command, Europe Command and Pacific Air Force Command bases around the world, monitors conventional attacks as well as nuclear, biological, or chemical attacks on a particular installation. Base commanders and decision makers then can determine how best to use their war-fighting assets and more importantly, how to protect military and civilian personnel via bunkers and protective clothing.

Exercise scenarios similar to those done with C-J and HPAC are done with great regularity in Operational Readiness Exercises using the TBMCS-UL mapping tool. Likewise, the GIS data supplied for TBMCS-UL may come from a variety of sources to include both government (NGA, FAA, Air Force Civil Engineers) as well as commercial vendors. Additionally, this collected data will be placed in a GIS repository and used for other Air Force visualization needs, such as Base Realignment and Closure 2005 (BRAC 2205) initiative.

The idea is that facility managers and sweep teams can use the map application as a reporting tool before, during and after an attack or incident occurs on an installation. Automated chemical and biological detectors also feed into the application. The tools can run from minimum data sources such as facility and runway map layers that have been vectorized/digitized from satellite imagery for remote locations, to a fully surveyed Garrison base, which can include additional layers from streets to golf courses. These exercises help commanders streamline recovery efforts and give them realistic expectations of a base's recovery time after an attack.

Whether preparing for or responding to domestic and global threats, the use of geospatial technology on homeland defense and emergency planning has been monumental since the events of Sept. 11. Regardless of whether GIS tools are supporting active military operations or incidents closer to home, having access to current data and the ability to analyze the data saves lives and property. Awareness of these tools/data, in addition to following data standards, can aid in increased interoperability while decreasing duplication of efforts.

Sensors & Systems | Monitoring, Analyzing and Adapting to Global Change | Stay in tune with the transformation. Subscribe to the free weekly newsletter.