[Geoldept] Fwd: Upcoming USGS Seminars (live webinars) of interest

Thu Nov 9 21:38:46 PST 2017

FYI, some great webinars coming up on Cascadia!
Eric

---------- Forwarded message ----------
From: Benjamin, Susan <sbenjamin at usgs.gov>
Date: Thu, Nov 9, 2017 at 3:00 PM
Subject: Fwd: Omnibus Seminar Announcement - November 9, 2017
To: GS-CAmnl All <gs-camnl_all at usgs.gov>

---------- Forwarded message ----------
From: Stock, Irene A. (ARC-SG) <irene.a.stock at nasa.gov>
Date: Thu, Nov 9, 2017 at 2:55 PM
Subject: Omnibus Seminar Announcement - November 9, 2017
To: "bphilibosian at usgs.gov" <bphilibosian at usgs.gov>, "epatlan at usgs.gov" <
epatlan at usgs.gov>, "afoster at usgs.gov" <afoster at usgs.gov>, "mwalton at usgs.gov"
<mwalton at usgs.gov>, "tswilson at usgs.gov" <tswilson at usgs.gov>, "
seingebr at usgs.gov" <seingebr at usgs.gov>, "jmtaron at usgs.gov" <jmtaron at usgs.gov>,
"dgarcia at usgs.gov" <dgarcia at usgs.gov>, "hdietterich at usgs.gov" <
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rniswon at usgs.gov" <rniswon at usgs.gov>, "smccann at usgs.gov" <smccann at usgs.gov>,
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"Smith, David J. (ARC-SCR)" <david.j.smith-3 at nasa.gov>, "Momeni
Hassan-harati, Mojgan (ARC-SS)[WYLE LABS]" <mojgan.momenihassan-harati@
nasa.gov>, "sbenjamin at usgs.gov" <sbenjamin at usgs.gov>, "Serrano, Josefina M.
(ARC-SC)[WYLE LABS]" <josefina.m.serrano at nasa.gov>, "Brosnan, Ian G.
(ARC-S)" <ian.g.brosnan at nasa.gov>, "Morrison, David D. (ARC-D)" <
david.morrison at nasa.gov>

*NASA Ames Science Directorate Weekly Omnibus Seminar Announcement*

November 9, 2017

*Please contact the seminar organizer to arrange access to either buildings
on the USGS campus, or to the Ames Research Center campus*.

NASA Ames Research Center Map:

https://historicproperties.arc.nasa.gov/map_bldglocator/map_
bldglocator_guide_2013.pdf

USGS Menlo Park Campus Map:

https://online.wr.usgs.gov/kiosk/mparea3.htm
<https://online.wr.usgs.gov/kiosk/mparea3.html>

*Earth Science / Code SG *

*November 13, 2017:* *High Flying Interns: Nine Years of NASA Student
Airborne Research, *Emily Schaller, SARP Project Manger, National
Suborbital Research Center and Melissa Yang Martin, Director, National
Suborbital Research Center, at Ames in Building N245, second floor
auditorium at 3:00pm. Abstract: The NASA Student Airborne Research Program
(SARP) is a unique summer internship program for rising senior
undergraduates majoring in any of the STEM disciplines. SARP participants
acquire hands-on research experience in all aspects of a NASA airborne
campaign, including flying onboard NASA research aircraft while studying
Earth system processes. Students are competitively selected each summer
from colleges and universities across the United States. They work in four
interdisciplinary teams to study surface, atmospheric, and oceanographic
processes. Participants assist in the operation of instruments onboard NASA
aircraft where they sample and measure atmospheric gases and image land and
water surfaces in multiple spectral bands. Along with airborne data
collection, students participate in taking measurements at field sites.
Mission faculty and research mentors help to guide participants through
instrument operation, sample analysis, and data reduction. Over the
eight-week program, each student develops an individual research project
from the data collected and delivers a conference-style final presentation
on their results. Each year, several students present the results of their
SARP research projects in scientific sessions at conferences such as AGU
and AMS. We discuss the results and effectiveness of the program over the
past nine summers and plans for the future.

*Space Biosciences / Code SC*

*Space Science & Astrobiology / Code SS *

*November 16, 2017: Martian Oceans: The Saturn System after Cassini-Huygens*,
Jeff Cuzzi, of Planetary Systems Branch, Building N201, Syvertson
Auditorium at 11:00am. Abstract:  The Cassini orbiter has just ended its
spectacularly successful 13 year orbital tour of Saturn, a mission that
began with the eye-opening descent of ESA's Huygens probe (first studied at
Ames) into the previously impenetrable atmosphere of the planet-sized moon
Titan. In this talk we will review what Cassini and Huygens have revealed
about Saturn, its dynamically evolving icy rings and moons, and the
fascinating "ocean worlds" Titan and Enceladus which are likely targets for
future NASA missions.

POC: mojgan.momenihassan-harati at nasa.gov

*External Seminars *

*USGS*

*November 14, 2017: Observations and patterns of volcanic seismicity across
the Cascades, *Weston Thelen  (USGS Cascades Volcano Observatory), USGS,
Menlo Park, Building 3, Rambo Auditorium, at 11:00am. Abstract: Volcanoes
in the Cascade Range of the United States exhibit significant variability
in their background seismicity rates in part due to differences in seismic
detection thresholds, but much of it is real and likely reflects
differences in conditions in the underlying magmatic-hydrothermal systems
at each volcano and the local tectonic stresses. Here we consider the
seismicity around each of the ten Very High Threat Cascade volcanoes, as
defined by the National Volcanic Early Warning System (NVEWS) threat
assessment, in order to determine what critical factors or processes may be
affecting the observed seismic behavior. Of these ten, four volcanoes are
consistently seismogenic when considering earthquakes within 10 km of the
volcanic center or caldera edge (Mount Rainier, Mount St. Helens, Mount
Hood, Lassen Volcanic Center (LVC)). Other Very High Threat volcanoes
(South Sister, Mount Baker, Glacier Peak, Crater Lake, Newberry Caldera,
Medicine Lake and Mount Shasta) have comparatively low rates of seismicity
and/or not enough recorded earthquakes to provide meaningful catalog
statistics.

We examine swarms of earthquakes (defined as three or more located
earthquakes per day above the maximum magnitude of completeness for all
catalogs) and find that earthquakes within a swarm account for about 60% of
seismicity at Mount St. Helens, Mount Hood and the LVC, but only 16% of the
earthquakes at Mount Rainier. We also find that seismicity within the upper
2-3 km of the volcano tends to be more constant in rate whereas deeper
earthquakes tend to be “swarmier.” Such behavior could reflect different
rheologic properties in the crust (e.g., higher strain rates are required
at greater depths) or different processes occurring in the shallower
(primarily hydrothermal) vs deeper (primarily magmatic) parts of the
volcanic systems.  Lastly, when considering the regional seismicity around
each volcano, it appears that volcanoes with relatively high rates of
background seismicity occur in areas that have relatively high rates of
regional seismicity.  Such a correlation suggests interactions of regional
stresses with local structures or dominant crustal fabrics may give rise to
high rates of seismicity on and off the volcano.  This has profound impacts
on the use of background rates of seismicity as a tool for long-term
monitoring.

USGS will be livestreaming the talk on the public Menlo Park livestream
site: (http://media.wr.usgs.gov/live/)  The talk will also be archived in
our calvo_seminar video archive folder on the internal server at the
following address: smb://130.118.11.13 from your Mac or \\130.118.11.13
from your PC.

As a reminder, the VSC seminar calendar lives here: https://volcanoes.usgs.g
ov/vhp/seminar/. Please let us know if you have any visitors who may be
interested in giving a talk.

*November 15, 2017: Seismic Site Characterization: Measure, Mark and Cut of
VS Profiles and VS30 Using a Flexible Multi-method
Approach, *Alan Yong, USGS, Earthquake Science Center, Pasadena, at USGS
Menlo Park, Building 3 Rambo Auditorium, Wednesday, November 15, 2017, at
10:30am. Abstract: The main considerations for modeling seismic ground
motions typically involve a trichotomy of effects that are partitioned into
source, path, and site. Site conditions—often representing no more than 1%
of the path from the seismic source—can strongly influence site response,
thus dominate the intensity of shaking. To account for this phenomenon, the
engineering community has traditionally used the index of VS30,
the time-averaged shear-wave velocity (VS) from the surface to a
depth of 30 meters. I present a review of the state-of-practice for
estimating VS30, as well as select developments for advancing
measured VS30 methods. VS30 values were traditionally
derived from direct borehole recordings of seismic travel-times. As a
result of cost and/or environmental factors that restrict the drilling of
boreholes, less-expensive noninvasive methods are now frequently used to
estimate VS30 values. Noninvasive methods com

monly involve the recording of active- or passive-source, surface-wave or
body-wave energy at the ground surface using multi-sensor arrays. Because
of the indirect nature of surface-based methods, their VS30
estimates can have substantial uncertainties. Moreover, surface-wave
analyses rely on the dispersive nature of Love or Rayleigh waves to derive
their frequency-dependent phase velocities, which are used as input to
inversion techniques that inherently yield non-unique solutions of
VS profiles. Despite limited data, conclusions from a number of
recent studies suggest that there is a trend towards supporting the
reliability of surface-wave based VS profiles and
VS30 values for use in site response analyses. We analyze
surface-wave dispersion data of more than two dozen sites where individual
surface-wave methods and combinations of different surface-wave methods
produced adequate wavelengths to model VS profiles to at least th

e requisite 30-meter depth. We find the inter- and intra-method variability
of the VS30 estimates generally remain insignificant (arithmetic
mean of 5% difference) despite substantial variability observed in the
equivalent VS profiles. At sites where the minimum recorded
wavelengths from each method did not satisfy the 30-meter depth criteria,
VS30 could not (by definition) be estimated by the individual
method, suggesting that reliable VS profiles for estimating
VS30 values are best developed using a combination of
complimentary methods. Additionally, we propose the use of the
Rayleigh-wave phase velocity at a wavelength of 40 m (VR40) as
derived from the site fundamental mode dispersion data to expedite
estimations of VS30 values. We find VR40-based
VS30 values correlate well with those derived from surface wave
methods (r2 = 0.99). Moreover, VR40 values can be

readily derived using a single-source two-receiver spacing configuration,
thus facilitating rapid data collection. It is also beneficial to use
VR40 values as a means to rapidly prescreen the subsurface for
lateral velocity variability or to supplement data where there are
insufficient records. For microzonation purposes, VR40 values
can also be used to densify sparse distributions of profile-based
VS30 point values. We, however, do not advocate circumventing
the development of VS profiles, as site-specific response
analyses require VS profiles. Direct reliance on VR40
values as the standalone approach is also not suggested because a complete
dispersion curve is necessary to confirm that the VR40 parameter
was indeed derived from the fundamental mode. In general, we recommend the
use of complementary methods to generate composite dispersion data because
we find the reliability of the resultant VS30</su

b> estimate of a site is consistently dependent on two key factors: the
flexible use of complementary methods that adequately record wavelengths to
resolve subsurface details to below the 30-meter depth and the quality of
the goodness of fit of the theoretical dispersion data to the
experimentally observed data for each method or combination of methods.

Webcast (live and archive):

https://earthquake.usgs.gov/contactus/menlo/seminars/1119

*November 16, 2017: Predicting Ground Motions from Magnitude 9 Cascadia
Earthquakes Using 3D Simulations, *Art Frankel, USGS, Menlo Park, Building
3, Rambo Auditorium, at 10:00am. Abstract: We have produced a large set of
broadband (0-10 Hz) synthetic seismograms for Mw 9.0 earthquakes on the
Cascadia megathrust by combining synthetic seismograms derived from 3D
finite-difference simulations (≤ 1 Hz) with finite-source, stochastic
synthetics (≥ 1 Hz). We used a compound rupture model consisting of high
stress drop M8 sub-events superimposed on large, shallower slip with long
slip duration, informed by observations of the M9.0 Tohoku, Japan and M8.8
Maule, Chile earthquakes. Fifty 3D simulations were run, considering a
variety of rupture parameters, to determine the range of expected ground
motions. For sites not in sedimentary basins, the spectral accelerations of
the synthetics are similar to the BC Hydro ground-motion prediction
equations for periods of 0.1-6 s, but exceed them at periods greater than 6
s. Response spectra from the synthetics show large basin amplification
factors of 2-5 at periods of 1-10 s for sites in the Seattle and Tacoma
sedimentary basins.

Webcast (live and archive): https://earthquake.usgs.gov/co
ntactus/menlo/seminars/1125

-- 
*Susan Benjamin  U.S. Geological Survey    Director, Western Geographic
Science Center*
*345 Middlefield Road
<https://maps.google.com/?q=345+Middlefield+Road&entry=gmail&source=g>, MS
531  Menlo Park, CA  94025  Office: 650-329-5049  FAX 650-329-4710  Cell
408-373-2355*
*sbenjamin at usgs.gov <sbenjamin at usgs.gov>
  http://geography.wr.usgs.gov <http://geography.wr.usgs.gov>*

-- 
Eric E. Grossman, PhD
Research Geologist, U.S. Geological Survey
Pacific Coastal and Marine Science Center
Tribal Liaison, USGS Natural Hazards Mission Area
Dept. of Geology, Western Washington University
516 High St, MS 9080, Bellingham, WA 98225
360-650-4697 (office)  831-234-4674 (cell)
email: egrossman at usgs.gov
http://walrus.wr.usgs.gov/climate-change/lowNRG.html
https://walrus.wr.usgs.gov/coastal_processes/cosmos/puget/index.html
<http://coralreefs.wr.usgs.gov/>
http://coralreefs.wr.usgs.gov/
http://puget.usgs.gov/

ooooo EXCUSE ME I DON'T MEAN TO IMPOSE, BUT I AM THE OCEAN ooooo
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