AEG: USGS’s Pratt on seismic shaking

Association of Environmental & Engineering Geologists

D.C. – Maryland – Virginia Chapter

Notice of Meeting

Thursday, October 19, 2017

Topic:                      Amplification of earthquake ground motions by Atlantic Coastal Plain sediments: Implications for Central and Eastern U.S. seismic hazards

Presenter:           Thomas Pratt, PhD
Research Geophysicist, U.S. Geological Survey

Damage in Washington, D.C., during the 2011 Mw5.8 Mineral, Va., earthquake was surprisingly high for an epicenter 130 km away, and “Did-You-Feel-It” felt reports suggest that ground motions in the city were amplified by Atlantic Coastal Plain and other unconsolidated deposits. We measure this potential ground amplification relative to bedrock sites in the city using teleseismic and regional earthquake signals recorded on a temporary seismometer array. The resulting spectral ratios show amplification in the 0.7 to 4 Hz frequency range, which overlaps resonant frequencies of buildings in the city as inferred from their heights, suggesting amplification at frequencies to which many buildings are vulnerable to damage. The 2011 earthquake thus emphasizes the importance of local ground motion amplification in stable continental regions, where low attenuation extends shaking levels over wide areas and unconsolidated, shallow deposits on crystalline or igneous bedrock can create strong contrasts in near-surface material properties. Thicker Atlantic Coastal Plain and Mississippi Embayment strata throughout the central and eastern U.S. produce strong fundamental resonance peaks in the 0.2 to 4 Hz frequency range on spectral ratios computed from crustal-scale seismic experiments. These spectral ratios can be converted from frequency to depth, resulting in depth-converted spectral ratios across the array that produce an image of the strata causing the resonances. The data sets thus provide an average velocity function for the sedimentary sequence, the frequencies and amplitudes of the major resonance peaks, and a subsurface image of the major reflectors producing resonance peaks, and show that teleseismic signals can be used to characterize sedimentary strata in the upper km.

Dr. Thomas Pratt is a research geophysicist at the U.S. Geological Survey’s Geologic Hazards Science Center within the Earthquake Hazards program. His research interests are in seismic imaging of fault systems beneath the surface, computer modeling of geologic structures, studying the tectonic settings of active faults, and understanding ground motions during earthquakes. His past research has focused on active faults throughout the continental U.S. and Alaska, as well as Japan and Panama, and ground motion studies in the Pacific Northwest and the eastern U.S. Dr. Pratt was based in Seattle, WA, for twenty years but recently moved to Reston, VA, where the primary focus of his research is earthquake hazards in the Central and Eastern United States. Dr. Pratt serves as Editor-in-Chief of the Bulletin of the Seismological Society of America, which is one of the premier scientific journals for earthquake science. He received his bachelor’s degree in geology at Cornell University in 1980, and his master’s (1982) and doctorate (1986) degrees in geophysics at Virginia Tech.
Meeting Information

Date/Time:                                                       Location:

Thursday, October 19, 2017              Amphora Restaurant

5:00 PM to 7:30 PM                             377 Maple Ave W

Vienna, VA 22180

Cost (dinner and meeting):                        Agenda:

Members                    $40                    5:00-5:30 PM     Social & Check-in

Non-members           $45                         5:30-6:15 PM     Dinner

  Discounts Available:                                           6:15-6:30 PM     Section Announcements &

      Students save $20                                                                     Sponsor Presentation

Retirees save $10                                          6:30-7:30 PM     Presentation followed by Q&A

A special thank you to our meeting sponsor:

Roctest, the leading manufacturer of geotechnical and structural monitoring instrumentation, has been in operation since 1967. In 2006, Roctest acquired Smartec SA, of Switzerland, specializing in the development, production and distribution of structural health monitoring systems using fiber optic technology. FISO Technologies, also in the Roctest family, leads development and manufacturer of fiber optic systems specializing in the aerospace, industrial control, energy and health sectors. Roctest is represented worldwide by an established network of partners in 75 countries.

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AEG DMV Officers (2017-2019)

Chair:  Drew Thomas, CPG
ECS Mid-Atlantic, LLC
(703) 471-8400

Vice Chair:  Katelyn Foster, PG
GeoStructures, Inc.
(703) 987-4499

Treasurer:  John Garber
ECS Mid-Atlantic, LLC
(571) 237-5865

Secretary:  Cheryl Gannon, CPG
(703) 418-3276


UMD: Martin on Saturn’s moons

2017 University of Maryland Geology Colloquium Series

Friday, October 20th 2017 at 3:00 pm
in PLS 1130, UMD College Park

Emily Martin
Smithsonian Institution

Exploring the tectonic histories of Saturn’s ocean worlds: from deep time to now.

Observations of Enceladus’s tectonic structures suggest that Enceladus may have expereienced punctuated episodes of tectonic activity. Similar populations of fractures on Dione and Rhea may also preserve evidence of varied stress histories within the fracture patterns expressed on their surfaces. Similarities and differences of the preserved fracture histories on these will inform the complex tectonic histories and geologic activity on these ocean worlds.

UMD: Echeverría on Geology Careers

2017 Geology Colloquium Series

Friday, October 13th 2017 at 3:00 pm
in PLS 1130, University of Maryland – College Park

Lina Echeverría
Corning Incorporated (Vice President of Science and Technology, Retired); Innovation Leadership Consultant

The Unpredictable Arc of a Career In Geology

Upbeat after the completion of postdoctoral and academic research, it feels safe to assume that life will continue along a straight road not unlike those lived by professors and colleagues who have surrounded us for close to three decades. This is particularly so when the experiences—college, graduate, post doc and beyond—have brought exploration and discoveries and, with them, excitement. From Buddhist philosophy we learn that life is what happens when we are busy making plans—and our clear plans may have surprising turns. As unexpected doors open in our lives, that same curiosity and willingness to venture of our early career will lead us into new territories, allow for contributions, and recreate excitement in totally unknown fields. We just have to be prepared to be surprised. Illustrating this narrative, I will share my career and life experiences, the unexpected turns from spinifex komatiites to the world of research and in! tellectual property in corporate America, and on to understanding the creative drive of individuals and harnessing it to deliver technology innovations.

October 18 meeting of the Paleontological Society of Washington

The Paleontological Society of Washington

7:00 pm, Wednesday, October 18

National Museum of Natural History, Constitution Ave. entrance

The Oldest Ceratopsians (and the Origin of Horned Dinosaurs) from a Fabulous Jurassic Fauna in Western China

Catherine Forster, Professor of Biology, George Washington University

Since 2001, The George Washington University and the Institute for Vertebrate Paleontology and Paleoanthropology have collaborated in expeditions to the Late Jurassic Shishugou Formation in Xinjiang Province, China. Field research there in the western reaches of the Gobi Desert can be extremely difficult due to high heat, wind storms, and occasional deluges, but it has also always been extremely productive. Through the years the expeditions have collected numerous new animals including crocodilians, turtles, lizards, cynodonts, and theropod, sauropod, and ornithischian dinosaurs. Notably, we have discovered the two earliest members of the Ceratopsia (horned dinosaurs), Yinlong and Hualianceratops. These discoveries show that the origin of this group extends well into the Jurassic, and morphology unique to these taxa strengthen the sister-group relationship between ceratopsians and pachycephalosaurs.

Non-Smithsonian visitors will be escorted from the Constitution Ave. entrance of the NMNH to the Q?rius auditorium at 6:50 and 6:55 p.m. Society members will host the speaker for dinner at the Elephant & Castle (1201 Pennsylvania Ave.) prior to the meeting. Members may meet at the restaurant or inside the Constitution Ave. entrance of the NMNH at 5:00 and walk to the restaurant as a group.

October 2017 Flyer.docx

UMD: NSF’s McKnight on Dry Valleys ecosystems

2017 University of Maryland Geology Colloquium Series

Friday, September 29th 2017 at 3:00 pm
in PLS 1130, UMD College Park

Diane McKnight

Glacial meltwater streams in the McMurdo Dry Valleys, Antarctica: ecosystems waiting for water

The McMurdo Dry Valleys of Antarctica is comprised of alpine and terminal glaciers, large expanses of patterned ground, and permanently ice-covered lakes in the valley floors, which are linked by glacial meltwater streams that flow during the austral summer. These valleys were first explored by Robert Scott and his party in 1903. In 1968 the New Zealand Antarctic Program began a gauging network on the Onyx River, a 32 km river that is the longest river in Antarctica. As part of the McMurdo Dry Valleys Long-Term Ecological research project, our research group has continued to monitor streamflow in the Onyx River and 15 other first-order streams in adjacent valleys. We have studied the linkages between hydrology, biogeochemistry and microbial community ecology in stream ecosystems through a period of climatic extremes. We found that the diatom community composition in the mats that are abundant in the streams varies with the flow regime. In the 1990! ’s a cooling period continued that was driven by atmospheric changes associated with the ozone hole. In the summer of 2001/002, this cooling period was interrupted by several warm and sunny summers that created “flood events” in the valleys and caused much greater ecological connectivity. During floods the microbial mats are scoured from the streambed and mat material is transported to the closed basin lakes. Thus, understanding the relationship between mat communities and hydrology may help in using diatoms preserved in lake sediments and perched deltas to reconstruct the hydrologic record beyond the limited instrumental record of the Dry Valleys.

Peter Brannen at NMNH on mass extinctions

An Evening with Peter Brannen: Envisioning the Future by Unlocking Earth’s Past

Tuesday, September 26, 2017
6:30 PM – 8:10 PM
Baird Auditorium, Ground Floor, National Museum of Natural History
10th St. and Constitution Ave. N.W.
Washington, DC 20013

The National Museum of Natural History invites you to attend an evening with award-winning science journalist, Peter Brannen. Using fossils and the Earth’s deep geological record, Brannen will explore groundbreaking research to broaden views on climate change and the role climate played in the most extreme catastrophes in the planet’s history.

Afterward, in a conversation with Kirk Johnson, Sant Director of the National Museum of Natural History, Brannen will discuss his new book, The Ends of the World. He will reveal how understanding the planet’s five mass extinctions can offer us a glimpse of our future and ask, “Are we on the brink of a sixth?”

The Ends of the World will be available for purchase and signing after the program.

This program was made possible through the generous support of David M. Rubenstein and is part of the An Evening With… signature series featuring thought leaders in conversation with paleontologist and Sant Director of the National Museum of Natural History, Kirk Johnson. 

This program is also part of the Deep Time Initiative, the Museum’s effort to lead the public on a dynamic journey through Earth’s 4.6-billion-year history to understand how our planet’s deep past connects to the present and our future.

AEG: Titus on The Pentagon & FEMA’s 9/11 Search and Rescue Mission

AEG-DMV Members and Friends,

Please join us for the September AEG-DMV Chapter meeting.

RSVP by Monday, Sept. 25!

Meeting Info:

Thursday, September 28, 2017

5:30-8:00 PM

Cooper’s Hawk Restaurant

19870 Belmont Chase Dr, Ashburn, VA 20147

Topic: The Pentagon – September 11th, 2011, FEMA’s Urban Search and Rescue Mission

Presenter: Leo J. Titus, Jr., P.E.,

President, ECS Mid-Atlantic

Mr. Titus was a civilian member of Fairfax County’s Urban Search and Rescue Team (VA-TF1) for 11 years and was one of the Structural Specialists deployed as part of the search, rescue, and recovery mission on September 11, 2001. Mr. Titus’ presentation will be an overview of the involvement of the FEMA Urban Search and Rescue teams at the Pentagon from September 11th through September 18th, 2001. There will be an emphasis on the damage to structural members and the shoring process used to stabilize the building during the first several days following the attack.

Please reserve a seat by Monday, September 25!

Two options for RSVP:

1) Reply to Cheryl Gannon ( and plan to pay in person (check or cash) at the meeting, or

2) Use the AEG-DMV website to RVSP and pay online via PayPal ( We are working on updating the website, so please ignore the incorrect dates. Contact Katelyn Foster ( if you have questions regarding the PayPal site.

A special thank you to our meeting sponsor:

Connelly and Associates Drilling Services

Geotechnical, Environmental, and Geothermal Drilling

Service Locations:

– 1513 Tilco Dr, Frederick, MD 21704

– 6882 Wellington Rd, Manassas, VA 20109

If you have questions or trouble viewing this email, please reply to Cheryl Gannon (