1. 2 Authority 1 3 Planning Area 1



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4.6.7 Pipelines


Throughout the Texas Gulf Coast Plain are numerous pipelines that transport crude oil, natural gas, and various petrochemical products. Pipelines are at risk for cracking or breaking, releasing potentially harmful chemicals into the environment. With the number or pipelines that intersect with the floodplain, flooding might also result in damage to pipelines.
In Pearland, numerous pipelines cross under the City, transporting crude oil, natural gas, and various petrochemical products. The heaviest concentration is in the southeastern part of the City, especially near Dixie Farm Road. Pipelines and the potential environmental impacts of a break, leak, or explosion are a real concern to City officials and residents of Pearland. Map 4-1 shows the locations of pipelines within the City. In the late ‘70s, an explosion resulted from a 36” natural gas pipeline at Stone and Max Road; no injuries were reported. Significant risk is present despite over 20 years without a reported incident.
As stated earlier in this section, numerous pipelines cross under the City, transporting crude oil, natural gas, and various petrochemical products (see Map 4-1). Given this fact and the fact that the entire City is only 44




square miles in size, it is estimated that all people and property within the City are at relatively the same degree of risk from pipelines. See Table 4-4 for an overview of people and assets at risk.


To estimate potential dollar value of losses to existing building, the City of Pearland evaluated prior loss data as reported by City officials. This data indicated that over the past 20 years, there have been no pipeline incidents within the City that have caused building damage. Due to the fact that there is no historical building damage as a result of pipelines, the estimated annual dollar value damage to existing or future buildings due to pipelines is near zero.

4.6.8 Seismic/Earthquakes


An earthquake is a sudden motion or trembling caused by an abrupt release of accumulated strain on the tectonic plates that comprise the Earth’s crust. Ground motion may be vertical or horizontal shaking. Figure 4-3 presents the general “earthquake risk” map prepared by the U.S. Geological Survey. It shows relative risk to compare seismic risks across the country. Most of Texas, including Pearland, is designated the lowest hazard rating.
In Pearland, seismic risks to people and property cannot be distinguished by area; the hazard is reasonably predicted to have uniform probability of occurrence (extremely rare) across the entire City. As listed in Table 4-4, all people and assets are considered to have the same degree of exposure.
Due to the extremely low probability of an earthquake within the City of Pearland and the fact that there is no record of any historical building damage as a result of seismic activity in the City, the estimated dollar value damage to existing or future buildings due to earthquakes is zero.

4.6.9 Landslides


The term landslide is used to describe the downward and outward movement of soils and rocks moving down a slope under the force of gravity. Landslides include mudflows, mudslides, debris flows, rock falls, rock slides, debris avalanches, debris slides, and earth flows. Most landslides are associated with heavy, prolonged rains which saturate soils.
In 1997, the U.S. Geological Survey published a national map to illustrate landslide risk areas. The map combines past incidents with a measure of “susceptibility”, defined as the “probable degree of response of rocks and soils to natural or artificial cutting or loading of slopes, or to anomalously high precipitation.” The entire Texas coastal plain, including Pearland, is shown has having had less than 1.5% of its land area affected by movement of soils on slopes (no planning period is identified).
In Pearland, landslide risks to people and property cannot be distinguished by area; the hazard is reasonably predicted to have uniform probability of occurrence (extremely rare) across the entire City. As listed in Table 4-4, all people and assets are considered to have the same degree of exposure.
Due to the extremely low probability of a landslide within the City of Pearland and the fact that there is no record of any historical building damage as a result of landslides in the City, the estimated dollar value damage to existing or future buildings due to earthquakes is zero.

4.6.10 Terrorism


The threat of terrorism has received significant media attention during the last few years. The September 11, 2001 terrorist attacks in New York City and Washington, DC, have heightened public concern and awareness about terrorism.

Terrorism is the use of force or violence against people or property in violation of the criminal laws of the United States for the purposes of intimidation, coercion, or ransom. The effects of terrorism can vary significantly, from loss of life and injuries to property damage and disruptions in services such as electricity, water supply, public transportation, and communications. Terrorist attacks can take a wide variety of forms, and can affect a small area (e.g., a building), or a large area (e.g., disrupted services for an entire city). Historically, bombings have been the most frequently used terrorist method in the United States.


In Pearland, the City’s Emergency Services has performed tabletop training exercises for responding to technological threats from terrorism – this training was performed in accordance with State of Texas guidelines. In addition, the City recently received a grant for approximately $134,000for training and equipment. Being in close proximity to the City of Houston and two major airports increases the vulnerability to terrorist incidents. Possible attack targets are broadly characterized as including freeways, airports, utilities, and chemical/industrial plants in the Houston and Pearland area. Pipelines, water treatment facilities, sewer treatment facilities, and other public facilities also are potential targets. Therefore, specific data on the vulnerability of these public facilities is not made available to the public.
Within the City of Pearland, terrorism risks to people and property cannot be distinguished by area; the hazard is reasonably predicted to have uniform probability of occurrence (extremely rare) across the entire City. As listed in Table 4-4, all people and assets are considered to have the same degree of exposure.
Given the lack of observed historical loss data from terrorism within the City of Pearland, no estimate of potential loss to existing or future buildings is available.



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