Tag Archives: earthquake
The Central U.S. is in Earthquake Country
There is no earthquake season. Earthquakes can cause damage at any time of the year. Earthquakes strike with little – if any warning, and can also occur in areas not considered to be in seismically active. This was seen with the widely-felt magnitude 5.6 earthquake quake near Shawnee Oklahoma November 6, 2011 and the magnitude 5.8 quake in Mineral, Virginia August 23, 2011.
May 30, 2013, at 10 a.m. (CDT), you can join experts from the Central United States Earthquake Consortium, the Insurance Institute for Business and Home Safety, and the Federal Emergency Management Agency, to learn how to protect your family and home from the impacts of earthquakes.
During this brief 45 minute webinar, you will learn more about:
- How to stay safe during an earthquake
- How to minimize earthquake related damages in your home
- Ways to protect your business from earthquakes and other disasters
- Common earthquake insurance questions
- How to find free earthquake safety resources and more…
To participate: RSVP by May 24, 2013 by emailing email@example.com. After you RSVP, you will be sent login instructions to join the webinar on May 30. Space is limited, so RSVP today!!!
Missouri lies in the The New Madrid Seismic Zone (NMSZ), the most active seismic area in the United States east of the Rocky Mountains. Small earthquakes are recorded in Missouri nearly every day. These earthquakes typically are too small to be felt but are recorded on seismographs, devices that measure the earth’s movement.
Earthquakes, landslides, sinkholes, soil liquefaction, rockfalls and even mine collapse occur in Missouri
A geologic hazard is one of several types of geologic events that can put lives and property in danger. In Missouri, geologic hazards consist of a wide range of phenomena and include: earthquakes, landslides, sinkholes, soil liquefaction, rockfalls and even mine collapse.
Most Missourians are familiar with the large 1811-1812 earthquakes that occurred in the New Madrid Seismic Zone (NMSZ) in southeast Missouri. However, Missouri experiences small earthquakes nearly every day. These earthquakes typically are too small to be felt but are recorded on seismographs, devices that measure the earth’s movement. While these earthquakes are more frequent in the NMSZ in southeast Missouri, they also occur on other faults located in Missouri and surrounding states.
Sinkholes are depressed or collapsed areas formed by dissolution of carbonate bedrock or collapse of underlying caves. Much of Missouri, especially the Ozarks, is underlain by bedrock susceptible to sinkhole development. Sinkholes are part of what is called “karst” topography and also includes caves, springs and losing streams. Aside from structurally impacting foundations of homes and other buildings, sinkholes often serve as direct conduits for rapid surface water infiltration into the underlying groundwater aquifer. Contaminants near or at the surface can quickly enter the aquifer and pollute drinking water supplies.
Landslides, slumps and rockfalls are potential geologic hazards throughout Missouri. They often can be triggered when surficial materials are disturbed or modified by man. Rockfalls are common hazards in areas that have bluffs or extremely steep hillsides. Landslides and rockfalls can vary in size from small to very large. In general, the higher and steeper the slope, the farther and faster the landslide or rockfall will travel.
Although man-made, collapsing mines also pose a geologic hazard. Abandoned mines occur throughout Missouri and include both surface pits and underground workings. Old mines were typically abandoned without proper reclamation or closure. These pits and underground voids can pose a public safety hazard.
Join us and millions of others Feb. 7, 2013 to participate in The Great Central U.S. ShakeOut! More than 2.4 million people across nine states participated last year by practicing how to protect themselves during earthquakes by DROPPING to the ground, taking COVER by getting under a sturdy desk or table, and HOLDING ON until the exercise ended.
This is Your Chance to Help
This earthquake was widely felt, and if you were living in the region at the time, it is scientifically important to note that you did or did not feel it. It was the strongest felt earthquake in southern Illinois since the M6.6 Halloween 1895 earthquake near Charleston, Mo.
In commemoration of the upcoming 45th anniversary of this important earthquake, the U.S. Geological Survey established a “Did You Feel It” site for people to record their shaking experience during this quake which was felt from Cleveland to Kansas City and Minneapolis to Atlanta.
The quake occurred at about 11 a.m. local time and geologists can learn from hearing from you. Your shaking experience will be converted to an Intensity map and scientists will use this information to strengthen a study of damage and intensity that was completed soon after the earthquake by the U.S. Coast and Geodetic Survey and St. Louis University.
This USGS website will ask for your zip code — where you were that day and the address — on that day (not now). This is needed only to help identify the differences in earthquake shaking from location to location. As you work your way through the website’s queries, it will ‘automatically’ measure scientific information about what you experienced. This information is very important to today’s earthquake scientists.
New computer modeling reveals much
Earthquakes rumble audibly and in infrasound (frequencies below the threshold of human hearing) and Thursday, a group of researchers will convene in Kansas City Mo., to present their findings about an unexpected source for the low-frequency sound – the pumping of the Earth’s surface. Attendees to the 164th annual meeting of the Acoustical Society of America will hear about infrasound frequencies generated by earthquakes from the group of researchers from New Mexico, Utah and Texas. Read more at phys.org. Learn about earthquakes in Missouri.
The Largest Quake in the Region since Winter 1811-12
A Magnitude 6.6 earthquake – the largest earthquake to occur in the central Mississippi River Valley since the 1811-1812 series in the area of New Madrid, Mo. – occurred near Charleston, Mo., on Halloween Day in 1895.
Structural damage and liquefaction phenomena were reported along a line from Bertrand, Missouri, in the west to Cairo, Illinois, in the east. Many sand blows were observed in an area southwest of Charleston, Missouri, and south of Bertrand, Missouri. Isolated occurrences of sand blows also were reported north and south of Charleston. The most severe damage occurred in Charleston, Puxico, and Taylor, Missouri; Alton, and Cairo, Illinois; Princeton, Indiana; and Paducah, Kentucky. The earthquake caused extensive damage (including downed chimneys, cracked walls, shattered windows, and broken plaster) to school buildings, churches, private houses, and to almost all the buildings in the commercial section of Charleston. – Abridged from Seismicity of the United States, 1568-1989 (Revised), by Carl W. Stover and Jerry L. Coffman, U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, Washington: 1993.
Earthquake occurrences in southeast Missouri are not rare. Sixty-eight earthquakes that ranged between Magnitude 2.0 and Magnitude 3.9 shook southeast Missouri from 2009-2011. The New Madrid Seismic Zone (NMSZ) is the most active seismic area in the United States east of the Rocky Mountains. The NMSZ is located in southeastern Missouri, northeastern Arkansas, western Tennessee, western Kentucky and southern Illinois. Southwestern Indiana and northwestern Mississippi are also close enough to receive significant shaking from large earthquakes occurring in the NMSZ. Learn more about the New Madrid Seismic Zone. Also, watch earthquake preparedness videos created by Missouri school children.
At 10:18 a.m. today, Californians and many others in the U.S., British Columbia, Southern Italy and other countries will take part in the Great ShakeOut, the largest earthquake preparedness drill to date. The Great ShakeOut earthquake drill helps people in homes, schools, and organizations improve preparedness and practice how to be safe during earthquakes. Check out the ShakeOut website for more information about today’s exercise.
Missouri participates in the Great Central U.S. ShakeOut every February, during Earthquake Awareness Month in Missouri. Last year, more than 2.4 million people across nine states participated by practicing DROPPING to the ground, taking COVER by getting under a sturdy desk or table, and HOLDING ON until the exercise ended.
Although not felt in Missouri, it was detected by several groundwater observation wells
September 5, 2012, a magnitude 7.6 earthquake rocked the Nicoya Peninsula of Costa Rica. The earthquake epicenter was approximately 25 miles beneath the earth’s surface and fortunately did not cause major damage. Earthquakes that occur at significant depths typically cause less surface damage but are commonly felt over a wide area. In the case of the Costa Rican quake, it was felt widely across Central America with some reports coming from as far away in Mexico.
Although it was not felt in Missouri, it was detected by several groundwater observation wells in Missouri’s network. The earthquake occurred at approximately 9:42 a.m. CDT and water levels in several of the observation wells show very rapid fluctuation. The water level in the Aurora, Mo. observation well shows a marked “step down” about the time of the earthquake, but also quickly recovered to expected levels. In all, a change of approximately 0.65 feet was observed in this well. This is an interesting phenomenon, but not entirely unexpected. The December 26, 2004 Sumatra earthquake was also detected.
Hydrogeologic responses to earthquakes have been well documented for many years. It is believed seismic waves that pass through the earth following a large earthquake induce expansion and contraction of an aquifer, in turn rapidly changing the pressures within the pore spaces where water is stored. The results can vary, but in this case a brief change in water levels is observed, albeit very small.
Learn about Missouri earthquakes.
How many magnitude 2.0 and greater earthquakes occurred from 2009-2011?
Earthquake occurrences in southeast Missouri are not rare, but in most cases are not felt on a widespread basis. Most Missourians know at least something about the New Madrid Seismic Zone and the historic earthquake events that took place in 1811 and 1812. During that time, numerous large earthquakes rocked the region almost continuously for two months. Although a large earthquake has not occurred along the seismic zone in many years, it is still an active fault zone and many small earthquakes occur every year. Most of these occur deep below the surface and are of a small magnitude. However, the region does generate several earthquakes per year that are felt by area residents. Sixty-eight earthquakes that ranged between Magnitude 2.0 and Magnitude 3.9 shook southeast Missouri from 2009-2011. Check out these maps on our website for locations of earthquakes in southeast Missouri.
Will Shaking Continue?