February 25-28, 2008 at the
Dunsmuir Lodge, Sidney, British Columbia
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To improve coordination among those involved in conducting research related to aseismic slip, non-volcanic tremor and earthquakes (episodic and otherwise)and communicating it to the public. Research activities involve documenting (e.g. making relevant measurements, disseminating and analyzing them) the related phenomena of non-volcanic tremor, aseismic slip, and earthquakes, interpreting them in terms of the underlying causative physical processes, and conveying results to other researchers and the public. Consideration also will be given to the implications for earthquake hazard assessment and how to capitalize on the education and outreach opportunities these phenomena present. information from elsewhere.
AgendaMonday Evening, (5:00 - 9:30 pm)
Poster Setup (4'x 4'), Room
260
(5:00-9:30)
Reception hosted by UNAVCO,
Peninsula Lounge (6:00-7:00)
Dinner (7:00-8:30)
Tuesday Morning Plenary
(9:00-12:00)
Three invited 30-minute
talks, a coffee break, two 15-minute contributed talks, 30 minute
discussion
"The phenomenology; the
observations of aseismic slip, non-volcanic tremor, related (temporally
and spatially) earthquakes."
Invited Speakers
Honn Kao, Pacific Geosciences Center, Geological Survey of Canada
David Shelly, University of California, Berkeley
Shinichi Miyazaki, Earthquake Research Institute, Japan
In addition to presenting overviews of what the basic observations are,
talks focus on some specific questions and topics, with examples
listed below.
What occurs when and where?
What are the spatial and temporal relationships between earthquakes
(large and small), tremor, and slow slip?
How regular are the intervals of slow
slip and tremor, temporally and spatially? How does the
regularity (or lack of) vary among regions where it occurs?
Dynamically triggered tremor.
Is dynamically triggered tremor the same phenomenon as tremor observed
with ETS? Does slow slip accompany it? What is its relationship to
triggered earthquakes? How widespread is it?
How ubiquitous are these
phenomena? Can we identify common or distinguishing
characteristics of regions where they are and aren't observed? Is it
missing in places where we might expect it (e.g. above creeping faults,
geothermal areas)?
The potpourri of slip events.
A wide range of seismic and aseismic signals have now been identified
and from them modes of fault slip inferred. How well do we really know
the latter? For example, how dependent are inferences on how tremor
'events' are defined? To what extent might measurements bias our
inferences (e.g. might GPS data be temporally or spatially aliased) or
might source and path affects be confused (e.g. when interpreting
spectral shapes)?
Where is tremor being generated?
Many models proposed to explain tremor rely on them originating
on the plate interface where slow slip is (inferred to be) occurring.
Thus it is critical to ask how we might reduce the large uncertainties
in tremor source location estimates, particularly their depths, and to
insure that the estimates obtained represent the full complement of
tremor sources and are not biased. For example, the most widely used
class of tremor location algorithms requires waveforms or their
envelopes that are coherent at numerous stations. To what extent does
this selectively extract the subset of the tremor population that are
deepest and on a single plane, and what fraction of the total population
is not located when such algorithms are employed?
Tuesday Lunch & Posters (12:15-2:00)
Tuesday Afternoon Working
Group Background Presentations (2:00-3:00)
These include invited
talks by people who also lead the later respective working group session
on the topic. The later working group sessions (2) are concurrent, but these
talks are not
E&O Needs & Opportunities
Working Group Convenor Presentation - 30 minutes
Convenor: Robert Lillie, Oregon State University
Where and what are the greatest needs? What works and doesn't work?
Opportunities for educating the public and invigorating the science.
Data and Instrumentation Working
Group Convenor Presentation - 30 minutes
Convenor: Evelyn Roeloffs, USGS, Vancouver, WA
What exists and what do we need?
Tuesday Afternoon Working
Groups (3:30-5:00)
These are concurrent, with
participants (except the Convenor) switching after 45 minutes.
E&O Needs & Opportunities
Working Groups
Convenor: Robert Lillie, Oregon State University
Working group to generate ideas for E&O within Earthscope, USGS, GSC, State
Geological Surveys and other programs.
Data and Instrumentation Working
Group
Convenor: Evelyn Roeloffs, USGS, Vancouver, WA
Working group to generate lists of the types of instrumentation we would
like to add over the next 10 years.?
Tuesday Dinner (6-7:30)
Tuesday Evening Working
Group Reports (7:30-8:00)
15 minutes presentation
from each working group Convenor (E&O Needs and Opportunities, Data and
Instrumentation)
Tuesday Evening Working
Group, Posters (8:00 - 9:30)
These two activities
are concurrent.
Chapman Conference Working
Group
Convenor: Joan Gomberg, USGS, Seattle, WA
Working group to identify Chapman conference Conveners, development of
text for soliciting a Program Committee, identification and plans to
solicit funding.
Posters
Wednesday Morning Plenary
(9:00-12:00)
This includes: Three
invited 30-minute talks, a coffee break, two 15-minute contributed talks,
concluding with a 30 minute discussion of outstanding issues raised
"The underlying physical
processes; observational constraints, theoretical models."
Invited Speakers:
Roy Hyndman, Pacific Geosciences Center, Geological Survey of Canada
Paul Segall, Stanford University, CA
Simon Peacock, University of British Columbia, Canada
In addition to presenting an overview of the classes of models currently
proposed, talks may focus on some specific modeling questions and
topics, with examples listed below.
What frictional models may explain
slow slip and/or tremor? A variety of frictional models have now
been proposed, each requiring specific loading conditions, constitutive
properties, degrees and types of heterogeneity, etc. How can these
models be verified observationally, what new modeling capabilities might
we need (e.g. more compute power), what are their shortcomings?
What can we learn from models and
observations that aren't based on seismic or geodetic data? Many
models/explanations of tremor and slow slip appeal to the presence of
fluids, either in static or changing conditions, but without rigorous
consideration of how and where fluids are likely to exist. What do
models and observations of fluid generation and flow in subduction zones
(e.g. from studies of volcanism), and elsewhere in the crust and
uppermost mantle, tell us about the feasibility of fluid-reliant
mechanisms of slow slip and tremor generation? Others have proposed that
long-lived fore-arc basins provide control on ETS processes. How might
the morphology and petrology be important?
Is the mode of slip of any particular
fault or fault patch a static feature? That is, based on
observations and predictions of theoretical models, do they slip
aseismically sometimes and seismically other times?
Wednesday Lunch (12:15-1:30)
Wednesday Afternoon
Plenary (1:30-2:30)
Two invited 30-minute
talks
"Implications for earthquake
hazards; what do users need/want to know and what do we need to do to
deliver this?"
Invited Speakers
John Vidale, University of Washington, WA
Jim Goltz, Caltech, CA
Talks address these questions, among others.
What does slow slip and tremor tell us
about the seismic potential of major fault zones? What is the
spatial correlation with locked faults/segments; how locked is locked
and how do we know?
When is it useful to make public
announcements and even predictions of ETS episodes? How should
this be done most effectively?
Wednesday Afternoon
Working Group Panel (2:30-3:00)
Panel on the User/Public Needs,
particularly those concerned with earthquake hazards.
Panelists:
Michael Reichle, California Geological Survey
Vickie McConnell, Oregon Dept. of Geology and Mineral Industries
George Crawford, Washington State Military Department
Maclaire Bolton, British Columbia Provincial Emergency Program
Representatives from Emergency Management Agencies, State Geological
Surveys, city and county governments discuss what information
related to slow slip and tremor might motivate them to take action, what
those actions might include, how they would like information delivered,
etc.
Wednesday PGC Field Trip 3:30-6 pm
Wednesday banquet 6:30-8:00 pm
Posters (8:00-9:00) pm
Thursday Morning Working
Groups (8:00-9:30)
These sessions are
concurrent, with participants (except the Convenor) switching after 45
minutes.
User/Public Needs Working
Group
Convenor: Selected Panel Member
Working group to generate action item list of approaches to meeting
public needs discussed in the panel.
Research Coordination Working
Group
Convenor: Ken Creeger, University of Washington, WA
Strategies for improving logistical coordination and information
exchange among research projects and groups (e.g. website or email
calendar of experiments, circulated updated reference list, blogs,
etc.), particularly among those in different disciplines.
Thursday Morning Working
Group Reports (9:30-10:00)
15 minutes presentation
from previous three working groups' Convenors (Chapman conference,
User/Public Needs, Research Coordination)
Thursday Morning Panel on
Future Directions (10:30-12:00)
Workshop summary and
'what next' presented by organizers
Thursday Lunch
(12:00-1:00)
Thursday afternoon
(1:30-4)
Working group to prepare outline of Workshop Summary (published as a
USGS Open-file Report or other publication) and EOS article.
