Earthquakes and Seismic Tremors: Is All U.S. At Risk?

Earthquakes and Seismic Tremors: Is All U.S. At Risk? Yes, as per earthquake risk maps generated by CAIT Research AssistantEarthquake rattles Dallas-Fort Worth area on September 30, 2012; Tremors in Washington DC and Virginia on August 23, 2011.

Numerous small tremors and on the average 19 major earthquakes occur globally each year. No state is free from earthquake risk in the United States. This was shown by Carrissa Beaseley in May/June 2011 Guest Post 1 who analyzed U.S. historical data of major earthquakes and created geospatial maps of seismic risk in the U.S.

Currently a graduate student at the University of Mississippi and CAIT Research Assistant, Ms. Carissa Beaseley has produced two more seismic risk maps. The first map compares historical 1895’s 6.8 magnitude earthquake at New Madrid, Missouri that affected a much larger area compared to a similar magnitude earthquake in California. The second map illustrates how many states, counties and population in a 200-mile radius around the New Madrid epicenter could be devastated by a future large earthquake event.


Historical Earthquake Map of the United States (map credit: Carrissa Beaseley)
Earthquake Risk Map of 200-km Radius Region around New Madrid, Missouri, the United States (map credit: Carrissa Beaseley)

Magnitude 3.4 earthquake rattles Dallas-Fort Worth Metropolis in the United States: The initial earthquake, measured at a preliminary magnitude of 3.4, struck at 11:05 p.m. CDT Saturday and was centered about 2 miles north of the Dallas suburb of Irving, the US Geological Survey’s national earthquake monitoring center in Golden, Colo., reported…the smaller aftershock with an estimated 3.1 magnitude occurred four minutes later and just a few miles away in another area west of Dallas. The Dallas-Fort Worth International Airport continued routine operations even though the shaking was felt at the airport, which is partly located in Irving’s city limits, airport public affairs officer David Magana said. He told AP that the airport, which has 1,800 daily departures and arrivals, had little air traffic late Saturday night. Irving’s emergency operators were flooded with more than 400 calls after the initial quake, with people reporting minor damage, such as cracks in some walls and a ceiling, pictures that had been knocked down and a report of a possible gas leak. USGS geophysicist Don Blakeman said Sunday… naturally occurring quakes can happen anywhere…. (credit: AP, ABCNEWS)

Magnitude 7.1 earthquake reported in Colombia, September 30, 2012: Colombian authorities say there are no immediate reports of injuries or damage from an earthquake centered deep underground in the country’s southwest whose magnitude the U.S. Geological Survey placed at 7.1. The USGS says the quake struck at 11:31 a.m. local time on Sunday 30 miles (48 kilometers) from the regional capital of Popayan. It says it was centered at a depth of 94 miles (150 kilometers). (credit: AP,

Rare great earthquake in April 2012 triggers large aftershocks all over the globe: Large earthquakes can alter seismicity patterns across the globe in very different ways, according to two new studies by US Geological Survey seismologists. Both studies shed light on more than a decade of debate on the origin and prevalence of remotely triggered earthquakes. Until now, distant but damaging “aftershocks” have not been included in hazard assessments, yet in each study, changes in seismicity were predictable enough to be included in future evaluations of earthquake hazards. This is a syndicated post, which originally appeared at ScienceDaily: Natural Disaster NewsView original post. September 26, 2012.

Large April 2012 earthquake triggered temblors worldwide for nearly a week: This year’s largest earthquake, a magnitude 8.6 temblor on April 11 centered in the East Indian Ocean off Sumatra, did little damage, but it triggered quakes around the world for at least a week, according to a new analysis by seismologists. This is a syndicated post, which originally appeared at ScienceDaily: Natural Disaster NewsView original post. September 26. 2012.

Study reveals complex rupture process in surprising April 2012 Sumatra earthquake: The massive earthquake that struck under the Indian Ocean southwest of Sumatra on April 11, 2012, came as a surprise to seismologists and left them scrambling to figure out exactly what had happened. Analysis of the seismic waves generated during the event has now revealed a complicated faulting process unlike anything seen before. This is a syndicated post, which originally appeared at ScienceDaily: Natural Disaster NewsView original post. September 26, 2012.  During the magnitude 8.7 earthquake, the Indo-Australian plate–a major tectonic plate that includes Australia and the surrounding ocean–ruptured over a complex network of at least four faults lying at right angles to one another. It was both the largest strike-slip earthquake and the largest intraplate earthquake ever recorded. The faults broke through the upper part of the plate and appear to have slipped as much as 35 to 40 meters during the quake….this is not a particularly hazardous type of earthquake, because the horizontal slip does not displace the water above the fault enough to generate a big tsunami and…present a lot of societal hazard…

Magnitude 8.7 earthquake was part of crustal plate breakup: Seismologists have known for years that the Indo-Australian plate of Earth’s crust is slowly breaking apart, but they saw it in action last April when at least four faults broke in a magnitude-8.7 earthquake that may be the largest of its type ever recorded. This is a syndicated post, which originally appeared at ScienceDaily: Natural Disaster NewsView original post. September 26, 2012.

Associate Press (AP) Interactive Tutorial on Earthquakes: “Thousand of earthquakes occur all over the world each day. Most are too small to feel. But on average there are 19 earthquakes each year that will be considered “major” or “great” according to the  U.S. Geological Survey.  The 1811 massive earthquake at New Madrid, Missouri caused landslides along the Mississippi River from southern tip of Illinois to Memphis.” (credit: AP)

Dr. Uddin’s Note: Destructive tsunamis are produced by earthquakes on ocean beds, such as 2004 Sumatra’s 9.3 earthquake and tsunami. An earthquake measuring 8.9 magnitude on the Richter scale hit the northeast coast of Japan on March 11, 2011 causing tsunami alerts throughout the Pacific Ocean. The 2011 Japan’s 8.9 earthquake and tsunami crippled the nuclear reactors of Fukushima power plant and led to one of the worst nuclear disasters in the world.

Seismic activities around the globe can be seen on the live world earthquake map available through the internet (USGS/Google). The USGS and NOAA have installed seismic monitoring stations in the U.S. and all over the world. In the case of tsunami it helps to provide early warning alerts to residents in the affected coastal communities. In earthquake prone Turkey there is a similar effort to monitor seismic tremors deep below ground in and around Marmara Sea.

Exploration drilling to monitor earthquakes in the Istanbul area, Turkey: Today the drilling starts for a seismic monitoring network on the Marmara Sea near Istanbul. Specially designed seismic sensors in eight boreholes on the outskirts of Istanbul and around the eastern Marmara Sea will monitor the seismic activity of the region with high precision. In each of the respective 300 meter deep holes several borehole seismometers will be permanently installed at various depths. These detect even barely perceptible earthquakes with very small magnitudes at a high resolution and can thus provide information about the earthquake rupture processes associated with these. This is a syndicated post, which originally appeared at ScienceDaily: Natural Disaster NewsView original post. September 7, 2012.

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