13 - RESOLUTION ADOPTING THE 2017 LAMAR COUNTY MITIGATION PLAN

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Lamar County Multi- Jurisdictional Hazard Mitigation Plan Chapter Three According to an Indian legend, a Caddo Indian chief was warned by the "Great Spirit" to move his village from the low lands. The Chief overlooked the warning and one day while he and his men were out hunting the gorund shook. When they returned, their village was gone beneath the water of the newly formed Caddo Lake. In 1811 New Madrid, Missouri had an earthquake that measured 8.9. This could have knocked down enough trees to form the great raft that dammed the Red River and formed Caddo Lake. Source:http://0ps.tamu.edu/X075bb/Caddolcaddo.htm/ HAZARD PROFILE: Section Ten - Earthquake 1. Description Over 100 earthquakes with a magnitude between three and six on the Richter scale have been recorded in Texas' history. Although most of those epicenters were far from Lamar County some of them wre felt by local residents. An earthquake is a sudden, rapid shaking of the earth caused by the breaking and shifting of rock beneath the earth surface. This sudden motion or trembling is caused by a release of strain accumulated within or along the edge or earth's tectonic plates. Earthquakes - The sudden rapid Tectonic plates lie below the Earth's crust. These plates are all moving in different directions at different speeds. These plates sometimes crash together pull apart, or even slide against each other. When this happens, it commonly results in an earthquake. 2. Location shaking of the earth caused by shifting of the rock beneath the earth's surface. — www.wikipedia.org All of Lamar County is equally susceptible to Earthquake. Earthquake is not limited to certain areas of the county or certain communities. It is regional in nature, covering vast expanses of the country. An extremely devastating earthquake centered several states away could affect Lamar County. With this in mind, all buildings and structures are equally susceptible to earthquake and its destruction. 3. Extent Earthquakes have a high potential for causing catastrophic casualties, property damage, and economic disruption. The extent of an earthquakes hazard depends greatly on the magnitude or size of the event. The magnitude is measured using the amplitude of ground motion as recorded on a seismograph. Figure 3 shows and compares the Richter or Local Magnitude Scale and the Modified Mercalli intensity Scale. An earthquake will only have one Magnitude number based on the epicenter. The same quake will have numerous MMI numbers with the largest nearest the epicenter and diminishing as the physical damages lessens. 131 Richter Scale or more recently Local Magnitude (M1) - Assigns a single number of quantify the amount of energy released by an earthquake. - www.wikipedia.org Modified Mercalli Intensity Scale (MMI) — used to measure an earthquake by quantifying the effects of the physical damage. — www.wikipedia.org