CHAPTER 2. Hazard Profiles and Loss Estimation
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CHAPTER 2. Hazard Profiles and Loss Estimation Following the guidance provided in FEMA’s mitigation planning how-to guide, Understanding Your Risks: Identifying Hazards and Estimating Losses (FEMA 386-2), the Jersey County Hazard Mitigation Planning Team initially reviewed local records and existing mitigation plans, conducted informal interviews with local experts from the public and private sectors – including emergency responders and individuals at institutions of higher education – and researched data available on state and federal Websites to ascertain the natural hazards that posed any potential risk to Jersey County. This initial stage of research indicated that additional research should be conducted on the following hazards: earthquakes, extreme heat, floods, hailstorms, land subsidence, severe winter storms, tornadoes, wildfires, and windstorms. Of these hazards, the following were deemed the most prevalent: earthquakes, floods, severe thunderstorms (a category that encompasses hailstorms and windstorms), severe winter storms and tornadoes. These natural hazards and their potential impact on the county are profiled in detail in this chapter. Justification for the exclusion of extreme heat, land subsidence and wildfires from this more detailed profile is provided in a concluding section at the end of this chapter. 2.1 Earthquakes General Information about Earthquakes For hundreds of millions of years, the forces of plate tectonics have shaped the Earth as plates move slowly over, under, and past each other. Most of the time, this movement is gradual. However, sometimes the plates lock together, creating tension. When the accumulated energy grows strong enough, the plates break free, causing the ground to shake. This sudden, rapid shaking of the earth caused by the breaking and shifting of rock beneath the earth’s surface is an earthquake.1 Shaking from earthquakes can collapse buildings and bridges, disrupt gas, electric, and phone services, or trigger landslides, avalanches, or fires. Injury and death can result from the effects of earthquakes as a result of collapsing walls, flying glass, falling objects, etc.2 The cost of this damage can be quite expensive, depending on the intensity of the affected area, the population of the affected area, and the preparedness of the community. For example, an earthquake in Northbridge, California, in 1994, a modern urban environment designed to withstand the forces of earthquakes, cost approximately $20 billion. A relatively small number of lives were lost: 33. In 1995, an earthquake in an unprepared Kobe, Japan, cost approximately $96 billion and at least 5,378 lives were lost.3 A severe natural disaster that occurred in northeastern Japan on March 11, 2011 began with a powerful earthquake off the northeastern coast of Honshu, Japan’s main 1 Effgen, Christopher. “Geological Information about Illinois.” The Disaster Center’s Illinois Page. 28 June 2003, <http://www.disastercenter.com/ illinois/illinois.htm> 2 Ibid. 3 Ibid Jersey County Natural Hazard Mitigation Plan April 2015 2-1 island, which caused widespread damage on land and initiated a series of large tsunami waves that devastated many coastal areas of the country, most notably in the Tohuoku region. The tsunami also instigated a major nuclear accident. The magnitude 9.0 earthquake struck at 2:46 p.m. Ultimately, the official total for the number of those confirmed dead or listed as missing from the disaster was about 18,500. In January 2010 a 7.0 magnitude earthquake killed more than 200,000 people in Haiti. The cost for reconstruction in the devastated areas was $155 billion.4 According to at least one estimate, a repeat of the New Madrid earthquakes of 1811-12, one of the largest earthquakes in U.S. history, could cost an estimated $60 billion in property losses in current dollars. The same report projected that an estimated 4,900 people in the Central United States would die from the event and 460,000 would be left homeless.5 Reference to the potential impact of another intense event along the New Madrid fault line is of particular interest to residents of Jersey County given the county’s position along this fault line and its continued activity to date. Figure 2.1.1 1811 New Madrid Earthquake Source: www.perdue.edu Frequency and History of Earthquakes Seventy to seventy-five damaging earthquakes occur every year in the world. In the United States, Alaska experiences the greatest number of large earthquakes; however, most of these quakes are located in uninhabited areas. California experiences the most frequent damaging earthquakes. The largest earthquakes felt in the contiguous United States were along the New Madrid Fault Line in Missouri (see Figure 2.1.1) where a three-month series of quakes from 1811 to 1812 included three quakes above a magnitude of 8 on the Richter Scale. This region has more earthquakes than any other part of the United States east of the Rocky Mountains. 4 www.britannica.com/Japan earthquake and tsunami of 2011 5 Beatley, Timothy and Philip Berke. “Time to Shake up Earthquake Planning” Issues in Science and Technology. Jersey County Natural Hazard Mitigation Plan April 2015 2-2 Figure 2.1.2 Earthquakes Affecting Jersey County Year Richter Mercalli The New Madrid Fault System extends 120 miles southward from Charleston, Missouri and Cairo, 1947 4.2 VI Illinois, following Interstate 55, to Marked Tree, Arkansas. It crosses five state lines and cuts across the 1953 4.0 VI Mississippi River in three places and the Ohio River in two places (see Figure 1). This fault experiences more 1955 4.3 VI than 200 events per year (1.0 or more on the Richter Scale). A damaging earthquake in this area, 6.0 or 1965 3.4 VII greater on the Richter scale, occurs about once every 80 years. A major earthquake, 7.5 or greater on the Richter 1968 5.2 VII scale, occurs approximately every 200-300 years. An earthquake above 8.0 on the Richter scale, such as the 1984 4.1 VI 1811-1812 Mississippi River Valley earthquakes, occurs about every 500-600 years. In June of 2011 a magnitude 3.9 earthquake occurred near Sullivan Missouri at approximately 3:10 a.m. local time. This earthquake was felt in 3 states by nearly 3500 people including Jersey County.6 How likely is a New Madrid earthquake? Using the same way as meteorologist forecast weather, earth scientists present forecasts of earthquakes as the chance of an earthquake occurring in a specific time interval. New research during the last 15 years in the Central United States has led to new discoveries that have led to new estimates of the probability of damaging earthquakes. Using past historical data and geological studies it can now be determined how often earthquakes reoccur. The data was also used to produce the National Seismic Hazard Maps, the USGS and the Center for Earthquake Research and Information of the University of Memphis now estimate that for a 50 year time period: Probability of a repeat of the 1811-1812 earthquakes (magnitude 7.5 – 8.0) = 10% Probability of a magnitude 6.0 or larger = 24 to 40%7 Illinois New Madrid Seismic Zone Scenario A rupture on the northeast extension of the New Madrid Fault produces intense shaking in southern Illinois. Forty counties near the source of seismic activity are identified as critical counties and are expected to incur high levels of damage and Jersey County is listed among them. The extensive damage to buildings in southern Illinois displaces tens of thousands of people. Nearly 51,500 people are displaced with most residing in the critical counties and approximately 15,000 are seeking temporary shelter while the remainder stay with family or friends outside the region. Over seven million square feet of space is required to house the shelter-seeking population. In addition, over 160,000 gallons of water and nearly 325,000 MREs would be required to feed this population for one week. The northeast segment rupture causes over 6,200 casualties in the State of Illinois with over 98% of those occurring in the forty critical counties. Numerous essential facilities are damaged and are not operational in the days after the earthquake i.e. schools, fire stations and police stations making it difficult for first 6 Mo. Dept. of Natural Resource/Geological Survey 7 USGS/Earthquake Hazard in the Heart of the Homeland/Joan Gombert & Eugene Schweig Jersey County Natural Hazard Mitigation Plan April 2015 2-3 responders to coordinate shelters. Transportation and utility lifelines are greatly reduced. Direct economic losses can be devastating.8 Figure 2.1.3 IEMA Regions and Earthquake Zones Source: IESD & National Environment Agency The Richter Scale is the most common measurement of earthquakes. It measures the magnitude of the earthquake, which is the total seismic energy released by the earthquake. The scale ranges from 3.5 to 8.1+. The earthquakes that have affected Jersey County have been as minor as 3.5 and as major as 8.0.9 The Modified Mercalli Intensity Scale, meanwhile, measures the intensity of earthquakes. Using the observations of people and descriptive reports, the Modified Mercalli Intensity Scale assigns a value of between I and XII to an earthquake. Jersey County lies mostly in zone VIII, meaning that earthquakes in this area are generally destructive. The northernmost tip of Jersey County lies in zone VII, meaning that earthquakes here are very strong 8 Impact of Earthquakes on the Central USA, Mid-America Earthquake Center, University of IL 9 “Earthquake History of Illinois” USGS. < http://neic.usgs.gov/neis/states/illinois/illinois_history.html>