Rohrback and Martin: Research That Rocks!

Science Seminar

Friday, September 18, 2015, CE Forum, Annandale Campus, NOVA

“Research That Rocks! Undergraduate Research at NOVA from Cliffs to Coasts to Climate Change!”


Robin Rohrback-Schiavone and Victoria Martin

11:30 – 11:55 am Light Refreshments and “Meet & Greet the Speakers” in the CE Forum


NOVA students are rocking the GeoSciences, taking advantage of unique opportunities for research and career exploration. Current student Robin Rohrback-Schiavone and former student Victoria Martin will discuss some of the projects NOVA geoscience students are involved in. These projects include petrographic analysis of basement rock beneath the 35-million-year-old impact crater in the Chesapeake Bay; using NOVA’s SEM (scanning electron microscope) to identify new morphotypes of calcareous nanofossils which shed light on climate shifts 52 million years ago; and the creation of a database of gigapixel-resolution geologic imagery (GIGAPan) for use by educators, professionals, and students.

Victoria Martin spent years finding out exactly what she didn’t want to do or be. Then, as a student at NOVA she decided to take a geology class as her science requirement. There she soon realized all those years of searching had come to an end. She had found her passion and the support of a dedicated team of Geology professors. She was also given the opportunity to work as a Learning Assistant for Oceanography, Physical Geology, and Historical Geology. She is a recent transfer to Cleveland State University, where she is a Lab Instructor for Physical Geology, and she is majoring in Environmental Science with a Geology concentration and G.I.S. Systems. Victoria has worked on research with the USGS that was presented earlier this year at the annual International Nannofossil Association conference in the Philippines, and will present at the National Geological Society of America meeting this year. She is interested in marine geology, limnology, micropaleontology, and paleoclimatology, a.k.a. “soft rock and old dead things.”

Robin Rohrback-Schiavone spent twenty years working as a stagehand and roadie before coming to NOVA. In her first semester, she took Geology 105 with Callan Bentley. Three weeks in, she realized, “Oh. This is what I want to do now.” Since then, she has taken every geology class NOVA Annandale has to offer. Having run out of geology classes to take, she now works for Callan Bentley on the Mid-Atlantic Geo-Image Collection (M.A.G.I.C.), using sophisticated imaging equipment to create extremely high-resolution images of geologic samples for professional and classroom use. She also works as a Learning Assistant for Shelley Jaye, aiding Mineralogy labs and overseeing Honors Mineralogy students performing petrographic analyses of a core sample from the basement rock beneath the Chesapeake Bay Impact Structure (CBIS). She has presented her work on M.A.G.I.C. and the CBIS core at the U.S. Geological Survey and at regional and national meetings of the Geological Society of America.

Presented by the Science Seminar Committee, Math, Science & Engineering Division, and the Lyceum, Annandale Campus, NOVA

PGS: Maurer on “The curse of dimensionality in exploring the subsurface”

2015 Near Surface Honorary Lecturer
The curse of dimensionality in exploring the subsurface
Presented by Hansreudi Maurer
ETH Zurich, Switzerland
The term “curse of dimensionality” refers to increases in the dimensionality of model spaces that result in undesirable increases in data sparsity, such that model parameters are no longer sufficiently constrained by the data. Although the term is usually employed in combinatorics, machine learning, and data mining, it is also directly relevant for many problems in exploration geophysics. The most obvious applications are 3D tomographic inversions, which typically include very large numbers of unknowns.
There is a further “curse of dimensionality” and related data sparsity that may impede many geophysical investigations: 3D surveys typically involve the acquisition of data using only a 2D array of sensors distributed across the Earth’s surface. As a consequence, procedures for imaging the subsurface are missing data recorded in the third dimension, depth. Similar problems affect 2D inversions of (1D) profile data.
Computational problems that need to be overcome in large-scale tomographic inversions are additional issues associated with the “curse of dimensionality”. In particular, the rapidly emerging field of realistic 3D full-waveform inversions of elastic and anisotroic data is hitting the limits of current computer facilities. Seemingly ever increasing computing power will undoubtedly be beneficial for such endeavors. Nevertheless, suitable model parameterizations that offer appropriate spatial resolution while keeping the inversion problem computationally tractable will continue to be critical elements of any high dimension inversion endeavor.
Because of the large computational costs and the difficulties to cover extensive areas with geophysical sensors in complicated terrain, many land surveys continue to involve data acquisition along profiles. Such surveys will play a significant role for the foreseeable future. When solving the associated 2D inversion problems, the “curse of dimensionality” strikes again. The underlying 2D assumption that subsurface properties and topography do not change in the third dimension, that is, perpendicular to the tomographic plane, is often unjustified.
The problem of data sparsity can be partially alleviated by employing optimized experimental design and optimized data parameterization approaches. These techniques identify experimental configurations and data representations that optimize data information content and resultant models in a cost-effective manner.
In this lecture, I will illustrate the “curse of dimensionality” by means of several examples from near-surface geophysics. I will present a variety of options for addressing the related problems, including experimental design techniques and optimized model parameterization strategies. I will also discuss problems and remedies related to out-of-plane features in 2D elastic full-waveform inversions.

Hansruedi Maurer is professor for exploration and engineering geophysics at ETH Zürich, Switzerland. His research interests span from algorithmic developments for geophysical tomography to innovative field studies concerned with natural hazards, storage of dangerous waste, exploration of deep geothermal reservoirs, cryosphere research and several other areas, where geophysical techniques provide useful information. A key aspect of his research is the tight coupling of latest developments in numerical modelling and inversion theory with the solution of problems that arise in field applications of magnetic, geoelectric, inductive electromagnetic, ground-penetrating radar and seismic methods. Moreover, he is one of the leading scientists in geophysical experimental design. His contributions in this relatively new research discipline were awarded with the Best Poster Award at the 1997 meeting of the Society of Exploration Geophysics and the 2004 Best Paper Award in Geophysics. He has served as an Editor for Geophysics, and he is an active member of several national and international scientific boards.

An invitation to join the Potomac Geophysical Society

Dear PGS Members and Associates,

It is my pleasure to invite you to join the Potomac Geophysical Society (PGS) for the 2015-2016 season. PGS is a local section of the Society of Exploration Geophysicists (SEG) and an affiliate society of the American Geophysical Union (AGU). Our goal is to encourage interaction among those in the region around Washington, D.C., who have an interest in geophysics or related earth sciences. Over the years, members of PGS have included individuals working in a broad range of government, academic, and private sector jobs.

PGS has continued to remain active and vital largely due to the interest of a dedicated group of loyal members. We would like to encourage you to be a part of this group. If you have not been a member, we ask that you join and attend this year. PGS cannot maintain its vitality without your support. PGS members receive a discounted price of $25.00 for dinner at the monthly meetings; non-members will be required to pay $30.00 for dinner. Members and non-members may attend the presentation only at no charge.

PGS will meet on September 24, 2015, (fourth Thursday); then will meet on the third Thursday of each month at the Officers’ Club at Fort Myer in Arlington, VA. The meetings typically include a social hour starting at 6:00 PM, followed by an optional dinner served at 7:30 PM, and a topical discussion by an invited speaker beginning at 8:30 PM. Our 1st Vice President, Marc Buursink, is busily working on arranging a very interesting series of talks for the upcoming season. If you have recommendations for speakers or discussion topics, any of the officers will be happy to hear from you.

For additional background, information, directions to the meetings, and breaking news about PGS, please check out our website at:

We hope you will be able to join us on a regular basis in 2015-2016. We look forward to seeing you!

On behalf of the PGS Officers,
Catherine Enomoto

President: Catherine Enomoto, U.S. Geological Survey,
1st Vice President: Marc Buursink, U.S. Geological Survey
2nd Vice President: Victor Oancea, SAIC
Secretary: Bob Fraser, U.S. Geological Survey (retired)
Treasurer: Joe Bennett, Leidos (retired)
Website Administrator: Jay Pulli, Raytheon BBN Technologies

Bentley to speak on local geology at Manassas library Sept. 15


​ The Mid-Atlantic region showcases two complete “Wilson cycles” of supercontinent formation and destruction. Though Virginia is mostly sedate today (occasional earthquakes notwithstanding), in the past the Old Dominion has been the site of Himalayan-scale mountain-building and rifting fully comparable to the Great Rift Valley of modern day East Africa. Award-winning NOVA geology professor Callan Bentley provides a fascinating tour of our region’s geologic history, looking at the modern landscape and interpreting these ancient tectonic events.

Tuesday, September 15, 2015, 7:00 p.m.

AEG/PGS: Conventional Tunneling at Tyson’s Corner

BWH Section of the Association of Environmental &

Engineering Geologists and the Potomac Geophysical Society

Date: Thursday May 21, 2015


Baltimore MD – Washington DC – Harrisburg PA

The Meeting will be held at the Amphora Restaurant, 377 Maple Ave., Vienna VA, 6:00-8:30pm. Reservations are necessary,  we need a head count for the restaurant, so, if you wish to attend dinner ($40, members; $45, non-members), please inform Bob Fraser by May 15th at 703-624-3965 (takes both voice and cell text messages) or via E-mail at Non-members and guests are welcome but must have a reservation. Let’s make this joint meeting a success: make a reservation!

TOPIC: Conventional Tunneling (SEM) at: Tysons Corner, Virginia

PRESENTER: Vojtech Gall, Ph.D., P.E. Gall Zeidler Consultants, Ashburn, VA

BIO: Dr. Gall is a Principal of Gall Zeidler Consultants, a tunnel engineering and consulting company headquartered in Northern Virginia. He has over twenty-five years of experience in the design, construction, and construction management of tunnels and underground structures. He frequently serves on expert review panels dedicated to the investigation and improvement of tunneling schemes ranging from initial inception stages through final design development at bid document level. His services relate to a wide variety of facilities ranging from hydro-power schemes in remote settings to complex transit structures at shallow overburden in difficult, over-built urban settings. He has led tunneling efforts on large infrastructure project such as Dulles Metrorail in DC, the Caldecott 4-th bore tunnel in San Francisco and the East Side Access project in New York City. He holds M.Sc. and B.Sc. degrees in Civil Engineering from the RWTH University in Aachen, Germany, a M.Sc. in Mineral Engineering from the University of Alabama and a Ph.D. in Civil Engineering from the University of Maryland. He is a registered Professional Engineer in 18 states and has authored over 40 technical publications on the subjects of tunneling.

ABSTRACT: The Metropolitan Washington Airports Authority (MWAA) is constructing the Dulles Corridor Metrorail Project (DCMP), which will extend Washington Metropolitan Area Transit Authority’s (WMATA) rail services from the Metrorail Orange Line in Fairfax County, Virginia to Route 772 near Ashburn in eastern Loudoun County, Virginia. The extension will be known as the Silver Line and once completed will add 23 miles to the existing Washington Metro System. The project was subdivided in two phases. Phase I segment is 12 miles long and involves 5 stations (two at grade and three elevated) and was opened to public in 2014. Phase II will extend the rail by another 11 miles with a station at Dulles International Airport and a terminus station in Ashburn.

Both phases use the design-build (DB) delivery method. Phase I was constructed by Dulles Transit Partners (DTP) a Joint Venture of Bechtel and URS and included twin 1,700 feet long single track, 22 feet diameter conventional tunnels (excavated by the Sequential Excavation Method or SEM) that are situated in the urban setting of Tysons Corner.

The presentation will address design and construction of these soft ground tunnels that emerged as the most feasible alternative to practically all other tunneling methods including open and closed face TBM drives and cut-and-cover techniques. Tunneling was accomplished with shallow overburden of as low as about 7 feet from the tunnel crown. Because of the shallow depth, soft ground conditions, and the need to control settlements, the tunnel design included use of a double row grouted pipe arch canopy as pre-support for the first 300 feet of excavation and a single row pipe arch canopy for the remaining length of tunnels thereafter. A real-time monitoring of the surface when tunneling the first 90 m under International Drive was implemented to assure VDOT of the tunneling performance.

USGS Mendenhall seminar: Mariana Islands seismicity & infrasound

Mendenhall Postdoctoral Research Seminar

John Lyons, USGS – Anchorage, AK

When: Monday, May 18, 2015 – 12 Noon

Where: Via WebEx and National Center, Room 3A409 (Chief Geologist’s Conference Room)


Long-period seismicity and infrasound driven by shallow magmatic degassing at Mount Pagan, Mariana Islands

Mount Pagan (570 m) is the currently active vent on the north end of Pagan Volcano, Mariana Islands.  Since the establishment of a monitoring network in 2013, a persistent degassing plume, long-period (LP) seismicity and infrasound, and infrequent small degassing explosions have dominated activity. The current low-level, open vent activity provides an ideal platform for studying the source processes of LP events, and how they relate to degassing. Many active volcanoes display LP (0.2-5 Hz) seismicity and because variations in LP activity often herald changes in eruption behavior, understanding the source mechanisms that generate LP events is a primary goal of volcano seismology. Expanding observations to include other data types greatly facilitates the interpretation of LP events. Studies correlating seismic and infrasound data have revealed important linkages between shallow LP seismicity and the generation of LP infrasound at other open vent, basaltic systems. Some form of degassing often accompanies LP activity, and integrating seismic and infrasound data with plume observations or gas chemistry allows further refinement of source models. In this study, we focus on characterizing the LP activity and interpreting the source processes generating the seismic and infrasonic signals through waveform modeling. The results are combined with gas emission and composition data and information about the shallow geologic structure to develop a model of shallow degassing for Mount Pagan.

WebEX Info

Topic: Mendenhall research Seminar
Date: Monday, May 18, 2015
Time: 11:00 am, Eastern Daylight Time (New York, GMT-04:00)
Meeting number: 714 351 061
Meeting password: (This meeting does not require a password.)
Host Key: 237217

Please verify the meeting topic above starts with the number of expected
connections, counting the presenter, for example:

Click the following link to view or edit your meeting information, or to start your meeting.

Teleconference: National Center in Reston, VA Dial In: x4848
DOI Dial In Number: 703-648-4848
Non-DOI Toll Free Dial In Number: 1-855-547-8255*
Security Code: 91930 followed by the # sign

Seth Burgess at USGS Reston: magmatism and mass extinctions

Special Seminar

Seth Burgess*, USGS – Menlo Park, CA

* Recipient of the 2014 Cozzarelli Prize (

When: Monday, April 27, 2015 – 11 AM

Where: Via WebEx and National Center, Room 1C400 (Visitor Center)


Using high-precision geochronology to test the link between magmatism and mass extinction

Broad temporal coincidence between select Phanerozoic instances of mass extinction and large igneous province (LIP) magmatism has led many to hypothesize a causal link between the two. Testing the plausibility of this connection depends on the tempo of both and their relative timing. Thus, dating the records of mass extinction and magmatism with the maximum possible precision and accuracy is critical. This presentation will detail the application of U/Pb thermal ionization mass spectrometry (TIMS) geochronology to (1) volcanic ash beds intercalated with the fossil record of the end-Permian mass extinction, and (2) lava flows, sills, and pyroclastic rocks of the Siberian Traps LIP. New dates permit a revised calculation of the tempo of magmatism and mass extinction and allow resolution of their relative timing.

WebEX Info

Topic: Mendenhall Fellow Talk: Seth Burgess

Date: Monday, April 27, 2015
Time: 10:30 am, Eastern Daylight Time (New York, GMT-04:00)
Meeting number: 719 125 959
Meeting password: (This meeting does not require a password.)
Host Key: 819447

Click the following link to view or edit your meeting information, or to start your meeting.

Teleconference: National Center in Reston, VA Dial In: x4848
DOI Dial In Number: 703-648-4848
Non-DOI Toll Free Dial In Number: 1-855-547-8255*
Security Code: 91930 followed by the # sign