1. Exploring Planet Earth Larry Braile Professor and Department Head Earth and Atmospheric Sciences College of Science Purdue University May, 2008 braile@purdue.edu http://web.ics.purdue/~braile When the Earth Shakes – Central United States Earthquakes http://web.ics.purdue.edu/~braile/new/EarthShakes.ppt

2. Exploring Planet Earth Outline The April 18, 2008 M5.2 SE IL earthquake and aftershocks Shaking of the ground - Seismogram playback Earthquake statistics Foreshocks, main shocks, aftershocks Frequency-Magnitude relationship Forecasting earthquakes Central United States earthquake history New Madrid earthquakes Seismic-Eruption software Causes of Central United States Earthquakes Efficient wave propagation in eastern North America Felt area and damage Comparison of CUS and CA seismograms Resources

3. Exploring Planet Earth The April 18, 2008 M5.2 SE Illinois earthquake and aftershocks April 18, 2008 M5.2 earthquake

4. Exploring Planet Earth The April 18, 2008 M5.2 SE Illinois earthquake and aftershocks April 18, 2008 M5.2 earthquake

5. LAT LON DEPTH DATE TIME (GMT) ( o N) ( o S) (km) Mag LOCATION 2008/04/18 09:36:59.00 38.45 -87.89 14.2 5.2 B 3.28 km SE of Gards Point,IL 2008/04/18 10:04:00.00 38.45 -87.86 13.4 2.2 B 2.89 km W of Odgen,IL 2008/04/18 10:06:06.00 38.44 -87.87 19.1 1.9 B 3.99 km W of Odgen,IL 2008/04/18 10:15:31.00 38.45 -87.84 16.4 1.6 B 1.16 km W of Odgen,IL 2008/04/18 10:36:33.00 38.46 -87.87 18.3 2.5 A 3.86 km W of Odgen,IL 2008/04/18 10:37:26.00 38.48 -87.86 14.2 2.1 C 4.25 km NW of Odgen,IL 2008/04/18 10:44:11.00 38.45 -87.85 16.2 1.6 B 2.02 km W of Odgen,IL 2008/04/18 10:46:24.00 38.44 -87.88 17.8 2.2 A 4.69 km SE of Gards Point,IL 2008/04/18 10:57:47.00 38.43 -87.92 17.2 1.5 B 5.00 km S of Gards Point,IL 2008/04/18 11:25:25.00 38.45 -87.87 15.3 1.2 B 3.77 km W of Odgen,IL 2008/04/18 11:55:58.00 38.44 -87.88 14.2 2.7 B 4.69 km SE of Gards Point,IL 2008/04/18 15:14:17.00 38.46 -87.87 15.5 4.6 A 3.86 km W of Odgen,IL 2008/04/19 03:05:53.00 38.44 -87.89 14.3 2.7 B 4.25 km S of Gards Point,IL 2008/04/19 09:46:44.00 38.44 -87.85 14.4 1.3 B 2.41 km SW of Odgen,IL 2008/04/19 12:45:38.00 38.45 -87.91 15.4 1.7 B 2.72 km S of Gards Point,IL 2008/04/19 16:55:17.00 38.44 -87.90 14.9 2.8 B 3.95 km S of Gards Point,IL 2008/04/20 05:02:42.00 38.44 -87.85 16.2 2.8 B 2.41 km SW of Odgen,IL 2008/04/20 05:31:42.00 38.45 -87.88 14.4 1.7 B 3.84 km SE of Gards Point,IL 2008/04/20 06:32:02.00 38.44 -87.84 16.5 1.0 B 1.75 km SW of Odgen,IL 2008/04/20 09:59:44.00 38.46 -87.84 13.8 1.3 B 1.45 km NW of Odgen,IL 2008/04/20 10:34:26.00 38.44 -87.90 17.1 2.3 A 3.95 km S of Gards Point,IL 2008/04/21 05:38:30.00 38.45 -87.88 18.3 4.0 A 3.84 km SE of Gards Point,IL 2008/04/21 07:58:46.00 38.45 -87.88 17.3 2.2 A 3.84 km SE of Gards Point,IL 2008/04/21 09:45:11.00 38.44 -87.90 17.1 1.2 B 3.95 km S of Gards Point,IL 2008/04/22 08:01:00.00 38.46 -87.90 13.7 1.6 B 1.87 km SE of Gards Point,IL 2008/04/23 01:32:33.00 38.45 -87.88 16.6 2.1 B 3.84 km SW of Gards Point,IL 2008/04/24 11:44:24.00 38.45 -87.90 18.3 2.6 A 2.88 km S of Gards Point,IL 2008/04/25 17:31:00.00 38.45 -87.87 13.0 4.2 A 3.77 km W of Odgen,IL 2008/04/28 21:46:59.00 38.45 -87.85 14.1 1.7 B 2.02 km W of Odgen,IL 2008/04/30 19:29:19.00 38.45 -87.87 15.4 2.6 B 3.77 km W of Odgen,IL 2008/05/01 05:30:38.00 38.45 -87.86 14.3 3.3 A 2.89 km W of Odgen,IL 2008/05/03 00:34:20.00 38.45 -87.86 16.1 1.4 B 2.89 km W of Odgen,IL 2008/05/29 10:49:28.00 38.44 -87.86 14.0 2.0 A 3.18 km W of Odgen,IL 2008/06/01 09:56:12.00 38.45 -87.85 14.2 1.6 B 2.02 km W of Odgen,IL 2008/06/05 07:13:15.00 38.45 -87.84 16.2 3.6 A 1.16 km W of Ogden,IL 2008/06/24 22:20:10.00 38.45 -87.86 14.6 2.9 A 2.89 km W of Odgen,IL 2008/07/18 02:58:56.00 38.44 -87.89 18.3 3.1 B 4.25 km S of Gards Point,IL April 18, 2008 M5.2 earthquake and aftershocks http://folkworm.ceri.me mphis.edu/catalogs/ht ml/cat_nm.html

6. http://news-info.wustl.edu/tips/page/normal/11630.html April 18, 2008 M5.2 earthquake and aftershocks

7. April 18, 2008 M5.2 earthquake Seismic reflection profile Wabash Valley faults Reflection Seismic Profiling of the Wabash Valley Fault System in the Illinois Basin U.S. Geological Survey Professional Paper 1538-O by R.M. René and F.L. Stanonis http://igs.indiana.edu/geology/struct ure/seismicProfiling/index.cfm

8. Seismic reflection profile over the Wabash Valley faults Seismic reflection profiling studies of a buried Precambrian rift beneath the Wabash valley fault zone; by John L. Sexton, L.W. Braile, W.J. Hinze, and M.J. Campbell; 1986; in Geophysics, Volume 51, Number 3 (March 1986).

9. Interpretive profile over the Wabash Valley faults M5.2 Eq (projected)

10. Shaking of the ground - Seismogram playback April 21, 2008 M4.0 SE Illinois aftershock

11. Exploring Planet Earth Earthquake Statistics Nov. 3, 2002 M7.9 Denali foreshock, mainshock, aftershocks

12. Magnitude of earthquake is controlled by fault length (or area) that ruptures Magnitude versus fault length (determined from aftershock zone length) for various earthquakes (Alaska, 1964; Denali, 2002; Landers, 1992; Loma Prieta, 1989; Northridge, 1994, etc.). Results were quickly obtained using Seismic/Eruption views. Alaska, 1964 Denali, 2002 Landers, 1992 Sumatra, 2004 Magnitude versus fault length Northridge, 1994 Loma Prieta, 1989 Fault rupture area controls magnitude

13. Denali aftershocks

15. DescriptorMagnitudeAverage Annually Great8 and higher1 ¹ Major7 - 7.917 ² Strong6 - 6.9134 ² Moderate5 - 5.91319 ² Light4 - 4.913,000 (est.) Minor3 - 3.9130,000 (est.) Very Minor2 - 2.91,300,000 (est.) ¹ Based on observations since 1900. ² Based on observations since 1990. Worldwide earthquakes per year (from USGS):

16. Worldwide earthquakes per year:

17. How many M6+ earthquakes each year? 6

18. Worldwide earthquakes per year: How many M6+ earthquakes each year? 6 ~150

19. Putting the earthquake risk in the U.S. into perspective… (Data from Stein and Wysession) Causes of death in the U.S., 1996 Cause of death Number of deaths Heart attack733,834 Cancer544,278 Motor vehicle accidents 43,300 Falling 14,100 Bicycle accidents 695 Severe weather 514 Football 18 Skateboards 10 Earthquakes (1811-1983), ave. per year 9 Earthquakes (1984-98), ave. per year 9

20. Earthquake Forecasting

21. ~0.01/year or 1 per 100 years (last one was 1895) ~0.7 per year ~7 per year M7+ earthquakes ~1 per 1000 years Large New Madrid earthquakes do not occur very frequently Earthquake Forecasting

22. The “New Madrid Earthquakes” Series of 3 major earthquakes (~M7- 7.5) December 16, 1811 January 23, 1812 February 7, 1812 Central United States Earthquake History

23. 12/16/1811 M7.3 1/23/1812 M7.0 2/7/1812 M7.5 After Susan Hough, http://pasadena.wr.usgs.gov/office/hough/scenario2.jpghttp://pasadena.wr.usgs.gov/office/hough/scenario2.jpg 12/16/1811 (dawn) M7.0 New Madrid 1811-1812 Earthquakes

24. Seismic/Eruption includes up-to-date earthquake and volcanic eruption catalogs and allows the user to display earthquake and volcanic eruption activity in “speeded up real time” on global, regional or local maps that also show the topography of the area in a shaded relief map image. Seismic/Eruption is an interactive program that includes a number of tools that allow the user to analyze earthquake and volcanic eruption data and produce effective displays to illustrate seismicity and volcano patterns. Viewing CUS Earthquakes http://bingweb.binghamton.edu/~ajones/ http://web.ics.purdue.edu/~braile/edumod/svintro/svintro.htm

25. Pattern of epicenters correlates with prominent positive gravity anomaly (caused by high density rocks in crust beneath sediments in the Mississippi Embayment). Gravity anomaly (smoothed) shown by colors and contours. Cause of New Madrid Earthquakes?

26. Gravity anomaly and pattern of epi- centers has been interpreted as being caused by an ancient buried rift complex.

27. Observed gravity anomalies (indicating that higher density rocks are beneath the surface below the Mississippi Embayment) and interpretive cross section of ancient rift structure.

28. Block diagram of buried rift structure. http://web.ics.purdue.edu/~braile/news/midwest.htm

29. Geologic Hazards Fact Sheet Earthquake Hazard in the Heart of the Homeland U.S. Geological Survey FS- 131-02 http://pubs.usgs.gov/fs/fs-131-02/fs-131-02.html http://pubs.usgs.gov/fs/fs- 131-02/fs-131-02.pdf

30. Efficient wave propagation in eastern North America

31. Intensity maps comparing intensity of shaking and expected damage for New Madrid and California earthquakes.

32. Intensity maps comparing intensity of shaking and expected damage for New Madrid and California earthquakes (http://geopubs.wr.usgs.gov/fact- sheet/fs017-03/)

33. Shake map (from S. Hough, USGS) intensity data for the Dec. 16, 1811 earthquake.

34. Shake map (from S. Hough, USGS) comparison for New Madrid and Landers earthquakes. significant and very widespread (due to low attenuation of seismic wave propagation in eastern N. America) When large New Madrid earthquakes do occur, the effects will be

35. Efficient wave propagation in eastern North America – Comparison of seismograms (~600 km) from CUS and CA M5.2 April 18, 2008 SE IL earthquake - unfiltered M5.2 April 18, 2008 SE IL earthquake– Low pass filtered 1 Hz M5.2 June 12, 2005 So. CA earthquake– unfiltered Note efficient high frequency wave propagation

36. Soft first story failure Loma Prieta earthquake, 1989, photo from USGS Examples of Earthquake Damage

37. Dec. 26, 2003 M6.6 Earthquake, Bam, Iran, ~80% of buildings destroyed Examples of Earthquake Damage

38. Shake table test of earthquake shaking (max. ~ 1 g acceleration) of two- story wood frame house, UCSD, July 2000. CUREE-Caltech Woodframe Project. Exploring Planet Earth Earthquake Shaking – Falling Objects

39. Background Information: The video footage shows a two-story house being tested by a simulated earthquake on a shake table at the University of California at San Diego on July 11, 2000. The test matched-up very severe ground shaking with very strong construction. The goal was to verify that a new house that conforms to all building code regulations and in addition is specially engineered can escape with little damage from such an earthquake. The testing was part of the CUREE-Caltech Woodframe Project funded by the Federal Emergency Management Agency (FEMA) through a grant administered by the California Governors Office of Emergency Services. The earthquake shaking provided by the shake platform replayed the actual motion of the ground that occurred in an area where the shaking was most intense in the January 17, 1994 Northridge Earthquake (Los Angeles). The peak acceleration is about 1 g at the base, and the roof moved with an acceleration of over twice that. The precise record of the jolts, or accelerations, of the shaking in the Northridge Earthquake was obtained by a strong motion seismograph, and this computerized record was then played back on the shake table at UC San Diego the way a sound recording, when played on high-fidelity sound equipment, recreates very closely the original musical performance. Click for MORE INFO on the test.MORE INFO http://www.abag.ca.gov/bayarea/eqmaps/fixit/videos.html

40. First floor – kitchen office – about 1 g peak acceleration.

41. Second floor – bedroom (upper level acceleration as great as 2 g).

42. Up Motion N-S Motion E-W Motion The horizontal directions of ground shaking are often significantly larger than the vertical direction due to the motion of shear and surface waves. Also note duration of strong shaking. Accelerograms (“acceleration seismograms”) ~7.3 km from Northridge epicenter 1 g of acceleration = 980 cm/s/s Accelerograms from M6.7 1994 Northridge earthquake

43. File to print 11 x 17 size color maps: http://web.ics.purdue.edu/~braile/edumod/CUSeqs/CUSeqsTwoMaps.doc Additional Resources:

45. http://rockyweb.cr.usgs.gov/outreach/mapcatalog/images/earthquake/central_ usa_earthquakes_3centuries.jpg

47. http://showme.net/~fkeller/quake/maps.htm

48. Earthquake Hazard Map – 5% probability of exceedance in 50 year period Geologic Hazards Fact Sheet Earthquake Hazard in the Heart of the Homeland U.S. Geological Survey FS-131-02 http://pubs.usgs.gov/fs/fs-131-02/fs-131-02.pdf The U.S. Geological Survey shaking-hazard maps for the United States are based on current information about the rate at which earthquakes occur in Different areas and on how far strong shaking extends from earthquake sources. Colors on this particular map show the levels of horizontal shaking that have a 1-in-50 chance of being exceeded in a 50-year period. Shaking is expressed as a percentage of g (g is the acceleration of a falling object due to gravity).