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Homeland Security

Scenario 9: Natural Disaster - Major Earthquake

Executive Summary

Casualties 1,400 fatalities; 100,000 hospitalizations
Infrastructure Damage 150,000 buildings destroyed, 1 million buildings damaged
Evacuations/Displaced Persons 300,000 households
Contamination From hazardous materials, in some areas
Economic Impact Hundreds of billions
Potential for Multiple Events Yes, aftershocks
Recovery Timeline Months to years

Scenario Overview:

General Description -

Earthquakes occur when the plates that form under the Earth's surface suddenly shift, and most earthquakes occur at the boundaries where the plates meet. A fault is a fracture in the Earth's crust along which two blocks of the crust have slipped with respect to each other. The magnitude of an earthquake, usually expressed by the Richter Scale, is a measure of the amplitude of the seismic waves. The intensity, as expressed by the Modified Mercalli Scale, is a subjective measure that describes how strong a shock was felt at a particular location.

The Richter Scale is logarithmic so that a recording of 7, for example, indicates a disturbance with ground motion ten times as large as a recording of 6. A quake of magnitude 2 is the smallest quake normally felt by people. Earthquakes with a Richter value of 6 or more are commonly considered major; great earthquakes have magnitude of 8 or more. The Modified Mercalli (MM) Scale expresses the intensity of an earthquake's effects in a given locality in values ranging from I to XII. The most commonly used adaptation covers the range of intensity from the condition of "I - Not felt except by a very few under especially favorable conditions," to "XII - Damage total. Lines of sight and level are distorted. Objects thrown upward into the air."

In this scenario, a 7.2-magnitude earthquake occurs along a fault zone in a major metropolitan area (MMA) of a city. MM Scale VIII or greater intensity ground shaking extends throughout large sections of the metropolitan area, greatly impacting a six-county region with a population of approximately 10 million people. Subsurface faulting occurs along 45 miles of the fault zone, extending along a large portion of highly populated local jurisdictions, creating a large swath of destruction. Soil liquefaction occurs in some areas, creating quicksand-like conditions.

Timeline/Event Dynamics -

While scientists have been predicting a moderate to catastrophic earthquake in the region sometime in the future, there were no specific indications that an earthquake was imminent in the days and weeks prior to this event.

Damage includes a large multi-state area of several hundred square miles. Rapid horizontal movements associated with the earthquake shift homes off their foundations and cause some tall buildings to collapse or "pancake" as floors collapse down onto one another. Shaking is exaggerated in areas where the underlying sediment is weak or saturated with water. (Note: In the central and eastern United States, earthquake waves travel more efficiently than in the western United States. An earthquake of a given size in the central and eastern United States may cause damage over a much broader area than the same size earthquake in California.)

Several hours later, an aftershock of magnitude 8.0 occurs. Based on past events, additional aftershocks are possible. Sizeable aftershocks (7.0 to 8.0 in magnitude) may occur for months after the original jolt.

Secondary Hazards/Events -

As a result of the earthquake, hazardous contamination impacts of concern include natural gas compression stations and processing plants, oil refineries and major tank farms, and natural gas/crude oil pipelines. In addition, more than 2,000 spot fires occur and widespread debris results. Flooding may occur due to levee failures and breaks in water mains and sewage systems.

Transportation lines and nodes; power generation and distribution; communications lines; fuel storage and distribution; and various structures (ranging from dams to hospitals) may be damaged and will require damage assessment in order to continue operating. Reduced availability of services will be disruptive and costly.

Ground shaking from the earthquake has generated massive amounts of debris (more than 120 million tons) from collapsed structures. In addition, fuel pumps in several gas stations have sustained damages, leaking thousands of gallons of gasoline into the streets. There are numerous reports of toxic chemical fires, plumes with noxious fumes, and spills. Several other local waste treatment facilities have reported wastewater and sewage discharges. A large refining spill has contaminated the port facility and is spilling into the harbor. Significant concern for spilled hazardous materials from storage, overturned railcars, and chemical stockpiles make progress very slow as triage is conducted.

Key Implications:

Approximately 1,400 fatalities occur as a direct result of the earthquake. More than 100,000 people are injured and continue to overwhelm area hospitals and medical facilities, most of which have sustained considerable damage. Approximately 18,000 of the injured require hospitalization. As many as 20,000 people are missing and may be trapped under collapsed buildings and underground commuter tunnels.

More than 1 million buildings were at least moderately damaged (40% of the buildings) and more than 150,000 buildings have been completely destroyed

Service disruptions are numerous to households, businesses, and military facilities. Medical services are overwhelmed and functioning hospitals are limited. Fire and Emergency Medical Services (EMS) stations and trucks were also damaged. Bridges and major highways are down or blocked and damaged runways have caused flight cancellations. There are widespread power outages and ruptures to underground fuel, oil, and natural gas lines. Water mains are broken. Wastewater primary receptors have broken, closing down systems and leaking raw sewage into the streets. As a result, public health is threatened.

More than 300,000 households have been displaced, and many businesses have lost employees and customers. The port has been adversely affected in its capacity to provide export/import and loading/unloading capabilities, and damage to vital parts of the communications infrastructure has resulted in limited communications capabilities.

The disruption to the nation's economy could be severe because the earthquake impacts major supply and transportation centers. Reconstruction, repairs, disposal, and replacement of lost infrastructure will cost billions of dollars. Replacement of lost private property and goods could also cost billions. An overall national economic downturn is probable in the wake of this event.

Mission Areas Activated:


Prevention/Deterrence/Protection - After the earthquake occurs, actions should be taken to protect critical facilities from terrorist attacks and to maintain civil order.

Emergency Assessment/Diagnosis - Disaster assessments and aerial reconnaissance are necessary. Using real-time seismic data, the Federal Emergency Management Agency (FEMA) runs an earthquake model to provide a preliminary "best guess" at the level of expected damage, subject to confirmation or modification through remote sensing and field assessments. Assessment teams must be deployed and remote sensing initiated.

Emergency Management/Response - Hazardous material spills must be managed. Emergency medical treatment, shelters, and food must be provided. A Joint Information Center (JIC) is established, and search and rescue teams must be place don alert, some of which should be activated and deployed. Public utilities and other basic-needs services must be repaired as quickly as possible, and damage assessments should be conducted.

Incident/Hazard Mitigation - Federal support will be required to coordinate the development of plans to execute mitigation efforts to lessen the effects of future disasters. Mitigation to minimize or avoid future impacts would largely be an issue for recovery and restoration.

Public Protection - Structural engineers are inspecting critical building, bridge, freeway, waste facilities, etc., and inspection teams are deployed to inspect hundreds of homes for safe habitability.

Victim Care - The massive number of injured and displaced persons requires a warning order for the activation of Task Forces for the delivery of mass care and health and medical services. Temporary housing strategies must be considered.

Investigation/Apprehension - Not applicable (natural disaster).

Recovery/Remediation - Hazardous materials will contaminate many areas, and decontamination and site restoration will be a major challenge.




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