PGS: Veith on Consistent Earthquake Magnitude Estimates

Please join us for the February 15, 2018 meeting of the Potomac Geophysical Society at 7:00 p.m. at the DoubleTree by Hilton McLean Tysons, 1960 Chain Bridge Road, 22102.  This location is within one-half mile of the Tysons Corner Metro station, near I-495, and has free parking available.  Our private meeting room is located in the back of the Orchard Cafe restaurant on the second floor of the hotel.  The optional dinner cost will be discounted to $30 for members in good standing (have paid dues) and students, and $40 for non-members, and is inclusive of iced tea, coffee, tax and gratuity.  Members and guests may attend the presentation after dinner for no charge; we estimate that the presentation will begin at 8:15 p.m.  For attendees who arrive early, social time will be held in O’Malley’s Pub on the first floor of the DoubleTree by Hilton hotel.  Drinks may also be purchased in the private meeting room on a cash basis.

In summary:

Social Time: 6:00-7:00 p.m. O’Malley’s Pub, first floor DoubleTree by Hilton

Dinner: 7:00-8:15 p.m. Orchard Cafe, second floor DoubleTree by Hilton

Meeting & Presentation: 8:15-9:30 p.m. Peachtree Room in the Orchard Cafe, second floor DoubleTree by Hilton

Note: This month we are again offering a special rate of $10 for student dinners when they present their current student ID cards.  We encourage you to attend to network with these students, and to spread the word about our meeting to the students that you work with.  As always, guests are definitely welcomed. We hope to see you there!

This month’s talk and speaker:

Toward Consistent Earthquake Magnitude Estimates – From all Seismic Phases

by Karl F. Veith, PhD, Consultant

Magnitudes were intended to be a measure of seismic event energy. But M b , M s , M L etc. do not necessarily give us the same value for ‘energy’. These magnitude values can vary by as much as 1 – 1.5 mu. To resolve this differential the relative energy levels for the various phases are estimated, relative magnitudes computed and the results compared for both strike-slip and thrust/normal faulting. Amplitude data from the International Seismological Centre bulletins for earthquakes from the western United States, Iran and Europe are analyzed for their relative energy content and the effects of source mechanisms on their ‘magnitude’ estimates for Pg, Lg, Pn, Sn, P, S, P’, and Rayleigh waves. Reliability estimates and the effects of station corrections are also evaluated.

Dr. Veith received a BS and MS in Geophysics from the University of Minnesota and a PhD in Geophysics from Southern Methodist University. He has over fifty years of experience, primarily in the field of arms control verification research.

We hope to see you next Thursday!


UMD: Boehnke on geochemical models through time

2018 University of Maryland Geology Colloquium Series

Friday, February 9th 2018 at 3:00 pm
in PLS 1140, UMD College Park

Patrick Boehnke
University of Chicago

Getting more out of geochemical data: Models for the Hadean to the Pleistocene

GSW 1527: Locatelli, Wesson, Bensi: fossilization, Darwin, hazards

The 1527th meeting of the Society will be on
Wednesday, February 7, 2018
featuring :

Emma Locatelli, U.S. State Department (formerly Yale)
It’s not just rust: biofilm-mediated clays help preserve fossil leaves

Robert Wesson, USGS (retired)
Darwin’s First Theory: Darwin and tectonics? Who knew?

Shelby Bensi, University of Maryland
Working across disciplines to improve resilience to natural hazards

Meeting flyer – Consider printing this out & posting it at your institution.

Beverages and socializing commence at 7:30pm.
The formal program starts at 8:00pm.
Meetings are open to the public; please join us!

We meet in the John Wesley Powell Auditorium of the Cosmos Club,
2170 Florida Avenue NW, Washington DC 20008.

Entrance is through the club gate, the first right-hand entrance on Florida Avenue north of the intersection with Massachusetts Avenue NW. The auditorium entrance is to the left of the gate. The Powell Auditorium is within walking distance of the DuPont Circle Metro stop (Q Street exit), the Connecticut Avenue bus routes (L2, L4), and the Massachusetts Avenue bus routes (N2, N4).

USGS: Wesson on Darwin the geologist

Scientist Emeritus Lecture Series
Darwin’s First Theory: Exploring Darwin’s Quest to Find a Theory of the Earth
Rob Wesson, USGS Scientist Emeritus
1:00 P.M., February 6, 2018
Most people know about Charles Darwin as the father of evolution, but what they don’t know is that his assignment on the HMS Beagle was as expedition geologist, to examine and interpret Earth features, not to study flora and fauna. Darwin’s seminal role in explaining the ups and downs of the Earth’s crust is the story told in Rob Wesson’s book, Darwin’s First Theory, and it is the fascinating story he will share with us in this lecture. Rob retraced Darwin’s steps in South America, Scotland, and Wales, and tackled the same questions about geologic processes that Darwin did. Rob explores the way Darwin conceived his theory of subsidence and uplift and how the concepts of the vastness of time, enormous impact of extremely slow change, and constant change in the environment all coalesced to form the foundation for Darwin’s subsequent discoveries in evolution.
Rob is an earth scientist, who as a kid, and an adult, has always loved a good story. His USGS career spanned four decades, and he continues geologic research as Scientist Emeritus. He is currently working with a team exploring the large earthquakes, tsunamis, and associated tectonics of Chile.

Paul Nadeau at NOVA: the US Shale Oil/Gas Revolution

Please join us for a presentation by Paul Nadeau (University of Stavanger, Norway) on “The US Shale Oil/Gas Revolution: A Historic Opportunity for America.” It will be at 12noon on Friday, February 9, in the CA 302 Auditorium (CA Building). I’ve seen Paul give this talk at GSW and it’s excellent – a neat blend of “state of the art” of fossil fuel extraction in the US, Norwegian socialist society, and how those two might merge in a giant submarine pipeline. Paul thinks outside the box, and is a lively raconteur – this is not to be missed! Free and open to the public. Please advertise the event to students.

UMD: Jackson on core formation

2018 University of Maryland Geology Colloquium Series

Friday, January 26th 2018 at 3:00 pm
in PLS 1140

Colin Jackson
Smithsonian Institution

Early episodes of high-pressure core formation preserved in plume mantle

GSW: Rudnick on Earth’s continents

The 1526th meeting of the Geological Society of Washington will be on
Friday, January 26, 2018
featuring :

GSW’s 125th birthday party and the Quasquicentennial Lecture:

Roberta Rudnick
University of California – Santa Barbara

“Earth’s Unique Continents”

Tickets are $90 apiece:

All attendees (including those only showing up at 8pm for the talk) need to:
1) register at the site linked to above, and
2) dress according to the formal dress code of the Cosmos Club