PGS: Louisa, VA earthquake sequence

The Potomac Geophysical Society, October 15, 2015–directions below:

Observations on The Louisa County Earthquake Sequence.

Keith L. McLaughlin

Abstract: At 13:51:04 EDT 23 August 2011, an Mw 5.7 earthquake occurred in rural Louisa County VA, near the small town of Mineral. The MMI VIII event was widely felt in 13 states and caused an estimated $200-300 Million damage. The event has been called “The largest and most damaging earthquake in eastern US since Charleston SC 1886”.  Aftershocks continue. While the Central VA earthquake zone has a history of moderate (MMI V-VII) earthquakes, the zone has historically been sparsely monitored. Two seismic stations between 100 and 300 km of the main shock provide a tantalizing historical data set that may be successfully exploited using modern waveform cross-correlation methods.  The main-shock was a complex rupture and the aftershocks are distributed over a significant volume with a range of focal mechanisms. These factors present a unique challenge to developing correlation-based methodologies to “mine for aftershocks” and search for un-reported events. I will present work in progress using these developing methods to investigate the Louisa Sequence.

Bio: Dr. Keith Lynn McLaughlin, Leidos Technical Fellow

Ph.D., Geophysics, University of California, Berkeley, 1983. “Spatial Coherency of Seismic Waveforms” M.S., Geophysics, University of California, Berkeley, 1980. B.A., Physics, University of California, Berkeley, 1974

Dr. McLaughlin’s specialty is physics-based statistical analysis of geophysical sensing (seismic, acoustic, and EM). He developed methodologies for event magnitude estimation, localization accuracy assessment, seismic, acoustic and EM adaptive signal-processing and physics-based target-based multi-mode multi-node fusion (M3NF) for MASINT exploitation architectures. Over the last three decades he worked on ground motion prediction (earthquake, explosion, machinery, vehicles, …), seismic and infrasound location, event discrimination, yield estimation, geothermal exploration, and persistent monitoring of human activities from unattended ground sensors. He was co-PI with VaTech under the DARPA Heterostructural Uncooled Magnetic Sensor (HUMS) program. He served as the PI and PM for the DTRA “IMS Group 2 Location Calibration Consortium”. He served as domain expert and US delegate to multiple bi-lateral and multi-lateral international conferences and workshops.

1998 to Present. Senior Scientist and Technical Fellow, Leidos (formerly SAIC).  Provides consulting and contributing technical services to multiple programs across the corporation. Serves as Chief Scientist, PI, and/or PM on multiple R&D efforts.

Meeting Room and Dining Arrangements: We meet in the glassed-in room at the back of the main dining room, The Fife and Drum. We order individually from the Club menu, which has a nice variety of dinner offerings. We pay a single bill, so we collect $25 from each member and $30 from each non-member. If a diner orders more than $20 in food and drink, he adds the amount over $20 to his contribution. The $5 overcharge goes to the Room Fee, Tax, Gratuity, and the Speaker’s Dinner. We collect on the Honor System. Reception is at 6:00 p.m. downstairs in the Old Guard Lounge. We order dinner at 7:00 p.m. The presentation is at 8:30 p.m. Please note that the meal orders will be taken at 7:00 p.m. Allow 15 minutes for security entering Ft. Myer as all civilian vehicles are searched. To ensure access to and from Fort Myer, use the Hatfield Gate, open 24 hours a day. Reservations are not necessary, however, we need a head count; so, if you wish to attend dinner, please inform Bob Fraser at 703-624-3965 or via email at If you wish, please feel free to attend the talk without dinner. Non-members and guests are welcome. Please send changes of address or email to

PSW: Carl Simpson on bryozoan polymorphs

The Paleontological Society of Washington

Wednesday, October 21, 7:00 pm, in the Cooper room (E-207A), National Museum of Natural History, Constitutional Ave. entrance

Determinants of bryozoan polymorphism

Carl Simpson

Department of Paleobiology, NMNH, Washington D.C. 20059

The members of a bryozoan colony can have dramatic morphological differences. When this occurs the modified members are termed polymorphs. The evolution of polymorphism is an old problem that has resisted understanding since Darwin. I test and reject a hypothesis of environmental control and propose another based on the construction of life-history strategies coupled with the origin of novel polymorph types.

Non-Smithsonian visitors will be escorted to the Cooper Room at 6:45 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 Constitutional Ave. entrance of the NMNH at 5:00 and walk to the restaurant as a group.

NWTRB deep borehole workshop Oct 20-21

The U.S. Nuclear Waste Technical Review Board will hold a workshop on Tuesday, October 20, and Wednesday, October 21, 2015, to evaluate technical and scientific issues associated with the potential use of deep boreholes to dispose of some radioactive wastes. The workshop is open to the public and there is no charge for attendance. The workshop will be held at the Embassy Suites Hotel, 1250 22nd Street NW, Washington, DC 20037; (Tel) 202-857-3388, (Fax) 202-293-3173. A press release on the workshop with additional details is available. The workshop agenda will be available on the Board’s website ( approximately one week before the meeting. The meeting will also be webcast through a link that will be posted on the Board’s website.

NWTRB Deep Borehole Workshop Press Release

UMD Geology: Buffett on the origins of Earth’s magneit field

2015 Geology Colloquium Series
Friday, September 18th 2015 at 3:00 pm
in PLS 1140
Bruce Buffett
University of California, Berkeley
Geomagnetic reversals and excursions: Insights into the origins of Earth’s magnetic field
Palaeomagnetic observations offer important insights into the origin of Earth’s interior, but a detailed reconstruction of the underlying dynamics is not feasible. A practical alternative is to construct a stochastic model for the time evolution of the dipole field. Slow changes in the field are described by a deterministic (drift) term, whereas short-time fluctuations are represented by a random (noise) term. Estimates for the drift and noise terms can be recovered from a time series of variations in the axial dipole moment over the past 2 million years. The results are used to predict a number of statistical properties of the palaeomagnetic field, including the average rates of magnetic reversals and excursions. A physical interpretation of the stochastic models suggests that reversals and excursions are part of a continuum of time variations in Earth’s magnetic field, arising from convective fluctuations in the core. Relatively modest changes t! he amplitude of convective fluctuations can produce large changes in reversal rates, including the well-known occurrence of superchrons lasting longer than 10 million years.

PSW: The [chemical] origin of life

The Paleontological Society of Washington

Wednesday, September 16, 7:00 pm, in the Cooper room (E-207A), National Museum of Natural History, Constitutional Ave. entrance

The [chemical] origin of life

Henderson Cleaves

Geophysical Laboratory, Carnegie Institution of Washington, Washington D.C. 20059

With the discovery of hundreds of extra-solar planets, scientists have been able to much more accurately fill in many previously unknown numbers of the Drake equation, which estimates the number of communicative civilizations which may exist in the Milky Way. Presently, the “bottleneck” unknown quantity is the number of planets on which life actually does arise, which is a reflection of how common conditions for the origin of life occur, and how easily the transition from non-living to living matter can take place. A brief history of the study of the origin of life and some current chemical perspectives on the problem will be presented.

Non-Smithsonian visitors will be escorted to the Cooper Room at 6:45 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 Constitutional Ave. entrance of the NMNH at 5:00 and walk to the restaurant as a group.

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.