EARTHQUAKES

A record of earthquake activity in Iowa.

Earthquake reported in the 1870s in Dubuque

EARTHQUAKES. Gigantic tremors of the Earth's crust capable of inflicting tremendous property damage. In Dubuque, the occurrence has generally created more excitement than physical damage.

That was not the case for anyone living in Dubuque in 1812. The New Madrid earthquake of February 7, 1812 had an estimated magnitude of 8.8. When Precambrian rocks snapped several miles below the surface in southeastern Missouri, boats were hurled from the MISSISSIPPI RIVER which flowed backwards for a distance, Reelfoot Lake was formed in Tennessee, and two steep rapids appeared in the river channel. Scientists estimate there is a 90% chance of another earthquake along the New Madrid fault of a magnitude of 6.0 by the year 2040. Estimates of another earthquake occurring comparable to the 1812 event range from 175 to 700 years. (1)

Tremors were felt in eastern Iowa on January 4, 1843. The next occurred in 1858. On April 24, 1867, distinct vibrations detected in Dubuque came from an earthquake centered in Manhattan, Kansas. (2) The tremors caused people in many Dubuque buildings to rush into the STREETS. (3) Plaster fell from walls. Residents of one downtown building later said they believed the walls were sinking due to a defective foundation.

People living on the second and third stories of buildings were especially affected by tremors on October 20, 1870. Lasting several seconds, the earthquakes caused considerable fear, but did little property damage.

Dubuque residents were again shaken on November 15, 1877. Students in the Fifth Ward School clung to their desks in fear. Dishes rattled. The belief, however, was that this quake was not as strong as the one experienced seven years before. On September 19, 1884 all Dubuque was shaken by an earthquake; it was particularly observed in high buildings. (4)

On August 31, 1886 three distinct earthquake shocks of twenty-five seconds' duration were felt. (5) The actual earthquake occurred in Raleigh, North Carolina, but its tremors reached as far as Dubuque and the island of Cuba. (6)

The entire state felt an earthquake on September 26, 1891. Two shocks struck Dubuque. Fortunately little damage was observed. On October 31, 1895, several distinct earthquake shocks of about thirty seconds' duration each occurred here. (7) While it did no structural damage, it did frighten many people. Shortly after 5:00 a.m., A. M. Riglar, the watchman in the SHOT TOWER felt the building sway and made a hasty retreat. (8)

One of the strongest earthquakes to strike Dubuque in the early twentieth century came in 1909. (9) Factories were jarred to the extent that workmen fled outside for safety. Employees in the BANK AND INSURANCE BUILDING claimed the feeling was like a heavy object had been dropped down the elevator shaft to shake the building at its foundation. They too fled to the streets. (10)

Tremors were again felt in Dubuque on January 2, 1912. Residents reported three distinct occurrences with again little property damage reported. People in downtown businesses compared the tremors to those caused by the movement of a heavy wagon on the street. (11)

In 1961 LORAS COLLEGE constructed Iowa's first seismograph station on campus. The station was one of four supplied by St. Louis University to different sites in the Midwest for a study of earthquakes and other seismic waves. (12) In 1964 shock waves from the Good Friday Alaskan earthquake, which struck Alaska at 9:36 p.m., reached the Loras station at 9:43 p.m. The force of the shock waves caused considerable movement in the earth's crust in the Dubuque area for up to fifteen seconds and broke one of the seismographs. (13)

Dubuque's history of earthquakes continued in 1968. On November 9th, tremors were from an earthquake centered in southern Illinois near the Indiana border were felt around the city with little damage done. (14) Workers in AMERICAN TRUST AND SAVINGS BANK and ROSHEK'S DEPARTMENT STORE reported pictures and light fixtures moving.

Another small tremor was felt in Dubuque in 2004. The earthquake, centered in north-central Illinois, had a magnitude of 4.5. (15)

Several geographic features of eastern Iowa suggest Dubuque could suffer significant damage from a major earthquake in the Midwest. (16) The New Madrid Rift Zone near St. Louis is a thin place in the earth's crust. The scene of three of the nation's biggest inland earthquakes in the past, the area now appears to be squeezing together causing tremendous pressure. A layer of stone called the Mississippi Arch would carry tremors along the MISSISSIPPI RIVER Valley. Layers of limestone containing CAVES, mines, and SINKHOLES could collapse. Mountain ranges and hot areas, which act to contain earthquakes and weaken them, are absent in this area.

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Source:

1. Anderson, Wayne R. Iowa's Geological Past: Three Billion Years of Change, Iowa City: University of Iowa Press, 1998, p. 5. Online: http://books.google.com/books?id=D2kzQ5RC4JMC&pg=PA5&lpg=PA5&dq=Loras+College+earthquake+%28dubuque%29&source=bl&ots=lNCa4L3MQY&sig=J-6dnel9xfH228dYLdHch6WhbCY&hl=en&sa=X&ei=qLuHUre9F8KGyAGd04CQBw&ved=0CFEQ6AEwBg#v=onepage&q=Loras%20College%20earthquake%20%28dubuque%29&f=false

2. "Historic Kansas Earthquakes Have Modern Significance," Courtland Journal, May 25, 1978, p. 3. Online: http://news.google.com/newspapers?id=PlplAAAAIBAJ&sjid=5pMNAAAAIBAJ&pg=2373,1843319&dq=earthquakes+dubuque&hl=en

3. Oldt, Franklin T., History of Dubuque County, Iowa. Chicago: Goodspeed Historical Association, 1880. Online: http://www.ebooksread.com/authors-eng/franklin-t-oldt/history-of-dubuque-county-iowa-being-a-general-survey-of-dubuque-county-histor-tdl/page-21-history-of-dubuque-county-iowa-being-a-general-survey-of-dubuque-county-histor-tdl.shtml (Number 21)

4. Ibid.

5. Ibid.

6. Fedler, Fred. "Earthquakes--The Days Dubuque Was All Shook Up," Telegraph Herald, January 22, 1964, p. 43. Online: http://news.google.com/newspapers?id=UXBFAAAAIBAJ&sjid=hrwMAAAAIBAJ&pg=1509,2767705&dq=earthquakes+dubuque&hl=en

7. Oldt, Franklin T., History of Dubuque County, Iowa. Chicago: Goodspeed Historical Association, 1880. Online: http://www.ebooksread.com/authors-eng/franklin-t-oldt/history-of-dubuque-county-iowa-being-a-general-survey-of-dubuque-county-histor-tdl/page-21-history-of-dubuque-county-iowa-being-a-general-survey-of-dubuque-county-histor-tdl.shtml (Number 22)

8. "Earth Trembles," Dubuque Daily Herald, November 1, 1895, p. 16

9. Fedler, Fred.

10. "Distinct Earthquake Felt in Several States," Youngstown Vindicator, May 26, 1909, p. 1. Online: http://news.google.com/newspapers?id=VqZIAAAAIBAJ&sjid=mIEMAAAAIBAJ&pg=1994,5308029&dq=earthquakes+dubuque&hl=en

11. "Earthquake is Felt in Dubuque," Telegraph Herald, January 2, 1912, p. 1. Online: http://news.google.com/newspapers?id=VBNeAAAAIBAJ&sjid=EWANAAAAIBAJ&pg=2714,416451&dq=earthquakes+dubuque&hl=en

12. "I. U. To Get Seismic Station," Warsaw Times-Union, March 25, 1961, p. 4. Online: http://news.google.com/newspapers?id=NR5SAAAAIBAJ&sjid=jTUNAAAAIBAJ&pg=2989,2849118&dq=earthquakes+dubuque&hl=en

13. Anderson, Wayne R.

14. Hansen, Christine. "Quake Jars Dubuque; No Damage is Reported," Telegraph Herald, November 10, 1968, p. 1. Online: http://news.google.com/newspapers?id=pDxRAAAAIBAJ&sjid=08QMAAAAIBAJ&pg=3663,6011918&dq=earthquakes+dubuque&hl=en

15. Hogstrom, Erik. "Earthuake Rattles Tri-State Windows," Telegraph Herald, June 29, 2004, p. 3. Online: http://news.google.com/newspapers?id=dJxdAAAAIBAJ&sjid=wlwNAAAAIBAJ&pg=6842,6631354&dq=earthquakes+dubuque&hl=en

16. Breyfogle, Bill. "Major Earthquake is Building; Would Be Felt in Dubuque Area," Telegraph Herald, Jan. 9, 1983, p. 18. Online: http://news.google.com/newspapers?id=8v9QAAAAIBAJ&sjid=J-IMAAAAIBAJ&pg=5359,951870&dq=earthquakes+dubuque&hl=en