Marianna Fault

Location of Marianna

The 'Marianna Fault' is a fault located near Marianna, Arkansas. The discovery was first announced by seismologists on January 21, 2009. It is not part of the more famous nearby New Madrid Seismic Zone,^[1] which is 100 kilometres (62 mi) away.^[2]

Haydar Al-Shukri, director of the Arkansas Earthquake Center at the University of Arkansas at Little Rock, discovered the Marianna Fault after searching for a fault since 2005.^[3] The fault line is seven miles long,^[4] with 110 metres (360 ft) dimensions.^[2] The land above the Marianna Fault is mostly cotton fields, but the presence of fertile soil with stretches of fine sand alerted seismologists to the fault's existence. It is believed that the Marianna Fault has previously experienced an earthquake that would have measured 7.0 on the Richter magnitude scale, and may well do so again.^[1] Al-Shukri believes that the fault was created 5,000 years ago.^[3]

Previously, the predicted earthquake damage Marianna, Arkansas, might have received from the more distant New Madrid Fault suffering a 7.0 earthquake would be 100% architectural and content damage, half of all bridges suffering some damage, 2,955 displaced residents, and loss of phones and electricity.^[5] The capital city of Arkansas, Little Rock, would also face damage.^[4] A major natural gas pipeline is located near the fault, and could be devastated by any such earthquake.^[1] Tennessee and Mississippi would possibly be affected as well.^[6]

In 2006, a letter to the Seismological Research Letters indicated the possible existence of a fault at Marianna. Sand blows in the area were similar in size to the New Madrid sand blows, giving rise to the speculation of a new fault. It was believed that the Marianna sand blows were created between 5000–7000 years ago.^[7] This followed a letter to the same journal a few months before saying that ground penetrating radar (GPR) was being used to study "large elliptical sand deposits" near Marianna.^[8]

Haydar Al-Shukri announced the discovery of the Marianna Fault on January 21, 2009.^[1] Days later Al-Shukri stated that more funding is required to study the fault, which would include studying if the fault is still active. The lack of seismic equipment in the vicinity is one factor in the need for additional funding.^[3]

The most recent earthquake activity in the area around the fault was located ten miles northeast of Marianna in August 2008. It measured 2.6 on the Richter scale. Few quakes have been felt in the area since 1994.^[3]

References

1. ^ ^{a b c d} Gambrell, Jon (January 22, 2009). "Scientist: New fault could mean major Ark. temblor". Associated Press. http://news.yahoo.com/s/ap/20090122/ap_on_re_us/arkansas_earthquakes. Retrieved 2009-01-28. ^{[dead link]}
2. ^ ^{a b} Al-Shukri, Haydar. "Haydar Al-Shukri Webpage". University of Arkansas at Little Rock. http://quake.ualr.edu/hja/hja.htm#1. Retrieved 2009-01-28. 
3. ^ ^{a b c d} Owens, Kendall (January 26, 2009). "Geologists: More study needed on fault line". Times-Herald of Forrest City, Arkansas. http://www.thnews.com/article.php?id=7426. Retrieved 2009-01-28. ^{[dead link]}
4. ^ ^{a b} "New Arkansas Fault to Cause "Major Disaster"?". Associated Press. January 22, 2009. http://news.nationalgeographic.com/news/2009/01/090122-arkansas-ea-AP.html. Retrieved 2011-03-04. 
5. ^ "Marianna, Arkansas". Arkansas Center for Earthquake Education and Technology Transfer. 1998. http://quake.ualr.edu/public/estimate/marianna.htm. Retrieved 2009-01-28. 
6. ^ "US scientists warn a newly discovered fault in Arkansas could trigger a magnitude seven earthquake". National Geoscience Database of Iran. January 25, 2009. http://www.ngdir.ir/News/NewsDetail.asp?PId=22001. Retrieved February 13, 2009. 
7. ^ "Very Large Earthquakes Centered Southwest of the New Madrid Seismic Zone 5,000–7,000 Years Ago". Seismological Research Letters (Seismological Society of America) (Seismological Society of America): 755–770. 
8. ^ "Three-Dimensional Imaging of Earthquake-induced Liquefaction Features with Ground Penetrating Radar Near Marianna, Arkansas". Seismological Research Letters (Seismological Society of America) (July 2006).