AGU is a worldwide scientific community that advances, through unselfish cooperation in research, the understanding of Earth and space for the benefit of humanity. Recent advances in understanding and predicting earthquakes, and seismic hazards in the Midwest Prof. Larry Braile, Purdue University American Geophysical Union Lecture NSTA Regional, Indianapolis, November 5, 2004 Department of Earth and Atmospheric Sciences  Copyright L. Braile. Permission granted for reproduction for non-commercial uses.

Topics: Earthquake sequences, or “How often do earthquakes occur?” Forecasting and predicting earthquakes Midwest earthquakes and hazards Earthquakes, seismology and plate tectonics in the classroom

Earthquake sequences: Main shock/aftershocks Foreshock, main shock, aftershocks Pairs (or triples) Swarm Random (long term)

Earthquake sequences: Main shock/aftershocks Foreshock, main shock, aftershocks Pairs (or triples) Swarm Random (long term)

Earthquake sequences: Main shock/aftershocks Foreshock, main shock, aftershocks Pairs (or triples) Swarm Random (long term)

Demo the Seismic/Eruption Program Available for FREE download Runs on Windows Plot earthquake epicenters, volcanic eruptions, relate to plate tectonics, and much more Program written by Alan Jones, SUNY, Binghamton

Magnitude of earthquake is controlled by fault length that ruptures (data for diagram generated using Seismic/Eruption program) 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. Graph can be logarithmic (as shown) or linear. Alaska, 1964 Denali, 2002 Landers, 1992

Earthquake sequences: Main shock/aftershocks Foreshock, main shock, aftershocks Pairs (or triples) Swarm Random (long term)

Earthquake sequences: Main shock/aftershocks Foreshock, main shock, aftershocks Pairs (or triples) Swarm Random (long term)

Mt. St. Helens Earthquakes (24-hour record) (photos from USGS) Harmonic Tremor, Mt. St. Helens

Earthquake sequences: Main shock/aftershocks Foreshock, main shock, aftershocks Pairs (or triples) Swarm Random (long term)

Time between M7+ earthquakes, Worldwide

Topics: Earthquake sequences, or “How often do earthquakes occur?” Forecasting and predicting earthquakes Midwest earthquakes and hazards Earthquakes, seismology and plate tectonics in the classroom

Earthquake forecasting and prediction: Frequency – magnitude relationship (probabilistic forecasting) Seismic gap Progression of main shocks Foreshocks Premonitory sequences (accelerated energy release, precursory chains) Other (EM signals, Radon gas emissions, animal behavior, etc.)

Earthquake forecasting and prediction: Frequency – magnitude relationship (probabilistic forecasting) Seismic gap Progression of main shocks Foreshocks Premonitory sequences (accelerated energy release, precursory chains) Other (EM signals, Radon gas emissions, animal behavior, etc.)

DescriptorMagnitudeAverage Annually Great8 and higher1 ¹ Major ² Strong ² Moderate ² Light ,000 (est.) Minor ,000 (est.) Very Minor ,300,000 (est.) ¹ Based on observations since ² Based on observations since Worldwide earthquakes per year (from USGS):

Worldwide earthquakes per year:

How many M6+ earthquakes each year? 6

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

Earthquake forecasting and prediction: Frequency – magnitude relationship (probabilistic forecasting) Seismic gap Progression of main shocks Foreshocks Premonitory sequences (accelerated energy release, precursory chains) Other (EM signals, Radon gas emissions, animal behavior, etc.)

Previous Large EQs Low level of activity prior to mainshock

Earthquake forecasting and prediction: Frequency – magnitude relationship (probabilistic forecasting) Seismic gap Progression of main shocks Foreshocks Premonitory sequences (accelerated energy release, precursory chains) Other (EM signals, Radon gas emissions, animal behavior, etc.)

Tectonics of Turkey, August 17, 1999 Kocaeli earthquake (from USGS Circular 1193)

Collapse of un-reinforced masonry buildings (from USGS Circular 1193)

Sinking of building caused by liquefaction (from USGS Circular 1193)

Seismograms (30 s long) Acceleration Velocity Displacement (modified from USGS Circular 1193)

Seismic waves demo Seismic waves and the slinky 4-page teaching guide Demonstrate P, S, Rayleigh and Love waves using a slinky Additional activities and teaching strategies included

Link to the 4-page slinky document:

The “5 slinky” model to demonstrate that seismic waves propagate in all directions and using travel time variations with distance to locate an earthquake A “favorite” demo

Kocaeli earthquake Istanbul Earthquake progression Next EQ? (modified from USGS Circular 1193)

Earthquake forecasting and prediction: Frequency – magnitude relationship (probabilistic forecasting) Seismic gap Progression of main shocks Foreshocks Premonitory sequences (accelerated energy release, precursory chains) Other (EM signals, Radon gas emissions, animal behavior, etc.)

If we could recognize foreshocks, many large earthquakes could be accurately predicted

Earthquake forecasting and prediction: Frequency – magnitude relationship (probabilistic forecasting) Seismic gap Progression of main shocks Foreshocks Premonitory sequences (accelerated energy release, precursory chains) Other (EM signals, Radon gas emissions, animal behavior, etc.)

Statistical analysis of space-time patterns of earthquake activity (training using historical record) allows recognition of precursory earthquake chains the precede main shocks. (from Keilis-Borok and others, SCEC/USGS/CGS EQ Prediction Workshop, 2004)

The M6.5 December 22, 2003 San Simeon earthquake was predicted using this method. However, the prediction window was 9 months (intermediate term) and the prediction area included a large part of California. Further, a subsequent prediction for the southern California area, using the same method, failed (prediction window ended 9/5/04). (from Keilis-Borok and others, SCEC/USGS/CGS EQ Prediction Workshop, 2004)

What is so special about Parkfield? A) On the San Andreas. B) A “repeating” earthquake series, ~M6, ~every 22 years. C) A magnitude 6 earthquake occurred there in 1857, 1881, 1901, 1922, 1934, and D) Starting point of the 1857 M8 Ft. Tejon earthquake. E) Last earthquake forecast for /- 2 years. EQ occurred Sept.28, (Modified from Figure from Rob Mellors, SDSU)

Earthquake forecasting and prediction: Frequency – magnitude relationship (probabilistic forecasting) Seismic gap Progression of main shocks Foreshocks Premonitory sequences (accelerated energy release, precursory chains) Other (EM signals, Radon gas emissions, animal behavior, etc.)

Topics: Earthquake sequences, or “How often do earthquakes occur?” Forecasting and predicting earthquakes Midwest earthquakes and hazards Earthquakes, seismology and plate tectonics in the classroom

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 ( ), ave. per year 9 Earthquakes ( ), ave. per year 9

However, the U.S. (except for Alaska) has not suffered a great earthquake (M8+) in almost a century. Further, the occurrences of the Loma Prieta (1989) and Northridge (1994) earthquakes demonstrate that significant loss of life and very large monetary damage can occur for strong to great (M6 to 8+) earthquakes, particularly if they are located near centers of population.

Soft first story failure Loma Prieta earthquake, 1989, photo from USGS

Soft first story failure Northridge earthquake, 1994, photo from USGS

(Bam, Iran earthquake, 2003, photo from USGS)

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

The “New Madrid Earthquakes” Series of 3 major earthquakes (~M7- 7.5) December 16, 1811 January 23, 1812 February 7, 1812

~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

Liquefaction, ground failure – a concern for future Midwest earthquakes because of presence of low elevation river deposits and liquefaction and sand blow observations from New Madrid earthquakes photo from USGS

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

Handouts: 4-page slinky teachers guide and one-page handout with outline of talk and Internet links. Additional Earth science sessions of interest today: Teaching Earth science in High School – teaching about earthquakes, Michael Wysession, CC 103, 12 Noon Earthquake detection and Analysis using digital seismic technology, J. Sayers and M. Hamburger, CC 102, 12:30 PM NESTA Earth and Space Science Share-a-Thon, Frank Ireton, Marriott 5, 2:00 PM NESTA Rock and mineral raffle, AW Rigsby and F Ireton, Marriott 5, 3:30 PM The PowerPoint presentation will be available on the Internet tomorrow AM (see link on one-page handout) Questions?  Copyright L. Braile. Permission granted for reproduction for non-commercial uses.

Extra Slides:

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.

Block diagram of buried rift structure.