exploring planet earth larry braile professor and department head earth and atmospheric sciences...

Exploring Planet Earth

Larry BraileProfessor and Department Head Earth and Atmospheric SciencesCollege of SciencePurdue UniversityMay, 2008braile@purdue.eduhttp://web.ics.purdue/~braile

When the Earth Shakes – Central United States Earthquakes

http://web.ics.purdue.edu/~braile/new/EarthShakes.ppt

Exploring Planet Earth

Outline

The April 18, 2008 M5.2 SE IL earthquake and aftershocks

Shaking of the ground - Seismogram playbackEarthquake statistics

Foreshocks, main shocks, aftershocksFrequency-Magnitude relationshipForecasting earthquakes

Central United States earthquake historyNew Madrid earthquakesSeismic-Eruption software

Causes of Central United States EarthquakesEfficient wave propagation in eastern North America

Felt area and damageComparison of CUS and CA seismograms

Resources

Exploring Planet Earth

The April 18, 2008 M5.2 SE Illinois earthquake and aftershocks

April 18, 2008 M5.2 earthquake

Exploring Planet Earth

The April 18, 2008 M5.2 SE Illinois earthquake and aftershocks

April 18, 2008 M5.2 earthquake

LAT LON DEPTH DATE TIME (GMT) (oN) (oS) (km) Mag LOCATION2008/04/18 09:36:59.00 38.45 -87.89 14.2 5.2 B 3.28 km SE of Gards Point,IL2008/04/18 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.memphis.edu/catalogs/html/cat_nm.html

http://news-info.wustl.edu/tips/page/normal/11630.html

April 18, 2008 M5.2 earthquake and aftershocks

April 18, 2008 M5.2 earthquake

Seismic reflection profile

Wabash Valley faults

Reflection Seismic Profiling of the Wabash Valley Fault System in the Illinois BasinU.S. Geological Survey Professional Paper 1538-O

by R.M. René and F.L. Stanonis

http://igs.indiana.edu/geology/structure/seismicProfiling/index.cfm

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).

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).

Interpretive profile over the Wabash Valley faults

M5.2 Eq (projected)

Shaking of the ground - Seismogram playback

April 21, 2008 M4.0 SE Illinois aftershock

Exploring Planet Earth

Earthquake Statistics

Nov. 3, 2002 M7.9 Denali foreshock, mainshock, aftershocks

Magnitude of earthquake is controlled by fault length (or area) that ruptures

Magnitude versus fault length (determined from aftershock zonelength) 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, 1994Loma Prieta, 1989

Fault rupture area controls magnitude

Denali aftershocks

Descriptor Magnitude Average Annually

Great 8 and higher 1 ¹

Major 7 - 7.9 17 ²

Strong 6 - 6.9 134 ²

Moderate 5 - 5.9 1319 ²

Light 4 - 4.9 13,000 (est.)

Minor 3 - 3.9 130,000 (est.)

Very Minor 2 - 2.9 1,300,000 (est.)

¹ Based on observations since 1900. ² Based on observations since 1990.

Worldwide earthquakes per year (from USGS):

Worldwide earthquakes per year:

Worldwide earthquakes per year:

How many M6+ earthquakes each year?

6

Worldwide earthquakes per year:

How many M6+ earthquakes each year?

6

~150

Putting the earthquake risk in the U.S. into perspective… (Data from Stein

and Wysession)

Causes of death in the U.S., 1996Cause of death Number of deaths

Heart attack 733,834 Cancer 544,278 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

Earthquake Forecasting

~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

The “New Madrid Earthquakes”

Series of 3 major earthquakes (~M7-7.5)

December 16, 1811January 23, 1812February 7, 1812

Central United States Earthquake History

12/16/1811M7.3

1/23/1812M7.0

2/7/1812M7.5

After Susan Hough, http://pasadena.wr.usgs.gov/office/hough/scenario2.jpg

12/16/1811 (dawn)

M7.0

New Madrid 1811-1812 Earthquakes

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

Pattern of epicenters correlates with prominent positive gravity anomaly(caused by high density rocks in crust beneath sediments in the MississippiEmbayment). Gravityanomaly (smoothed)shown by colorsand contours.

Cause of New Madrid Earthquakes?

Gravityanomaly and pattern of epi-centers has been interpreted asbeing caused by an ancientburied riftcomplex.

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

Block diagram of buried rift structure.

http://web.ics.purdue.edu/~braile/news/midwest.htm

Geologic Hazards Fact SheetEarthquake Hazard in the Heart of the HomelandU.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

Efficient wave propagation in eastern North America

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

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

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

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

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

Soft first story failure

Loma Prieta earthquake, 1989, photo from USGS

Examples of Earthquake Damage

Dec. 26, 2003M6.6 Earthquake,Bam, Iran,~80% of buildingsdestroyed

Examples of Earthquake Damage

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

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.http://www.abag.ca.gov/bayarea/eqmaps/fixit/videos.html

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

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

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 a

ccel

erat

ion

= 9

80 c

m/s

/sAccelerograms from M6.7 1994 Northridge earthquake

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

Additional Resources:

http://rockyweb.cr.usgs.gov/outreach/mapcatalog/images/earthquake/central_usa_earthquakes_3centuries.jpg

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

Earthquake Hazard Map – 5% probability of exceedance in 50 year period

Geologic Hazards Fact SheetEarthquake Hazard in the Heart of the HomelandU.S. Geological Survey FS-131-02

http://pubs.usgs.gov/fs/fs-131-02/fs-131-02.pdf

The U.S. Geological Surveyshaking-hazard maps forthe United States are basedon current informationabout the rate at whichearthquakes occur in Different areas and on how far strong shaking extendsfrom earthquake sources. Colors on this particularmap show the levels of horizontalshaking that have a1-in-50 chance of beingexceeded in a 50-year period. Shaking is expressed asa percentage of g (g is the acceleration of a falling object due to gravity).