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SCEC/ITR Project SCEC/ITR Project
First Annual Report

Performance Period: Oct 1, 2001September 31, 2002

Thomas H. Jordan, Principal Investigator
Introduction

The Southern California Earthquake Center (SCEC), in collaboration with the San Diego
Supercomputer Center, the Information Sciences Institute, the Incorporated Research Institutions
for Seismology, and the U.S. Geological Survey, has received a five-year grant from the National
Science Foundations Information Technology Research (ITR) Program and Geosciences
Directorate to build a new information infrastructure for earthquake science. Project goals have
been formulated in terms of four computational pathways related to seismic hazard analysis
(SHA). Pathway 1 involves the construction of an open-source, object-oriented, and web-enabled
framework for SHA computations that can incorporate a variety of earthquake forecast models,
intensity-measure relationships, and site-response models. Pathway 2 aims to utilize the
predictive power of wavefield simulation in constructing intensity-measure relationships.
Pathway 3 will incorporate fault-system models into time-dependent earthquake forecasts.
Pathway 4 concerns the assimilation of various types of data into the unified structural
representation of Southern California required by the other pathways. The overall goal is to
create a SCEC community modeling environment or collaboratory that will comprise the
curated (on-line, documented, maintained) resources needed by researchers to develop and use
all four of these computational pathways.
Figure 1. Computational pathways that
will be facilitated by the information
infrastructure developed in the
SCEC/ITR Project. (1) Current
methodology for probabilistic seismic
hazard analysis. (2) Ground-motion
prediction using an anelastic wave model
(AWM) and a site-response model
(SRM). (3) Earthquake forecasting
using a fault-system model (FSM) and a
rupture-dynamics model (RDM). (4)
Inversion of ground-motion data for
parameters in the unified structural rep-
resentation (USR), which includes 3D
information on active faults, tectonic
stresses, and seismic wave speeds. The
SCEC/ITR Project has focused first-year
efforts on Pathways 1 and 2.

The short-term objectives of the project have been focused on Pathways 1 and 2. Specific
activities include (1) the development and verification of the computational modules, (2) the
standardization of data structures and interfaces needed for syntactic interoperability, (3) the
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1 development of object classes, control vocabularies, and ontologies for knowledge management
and semantic interoperability, (4) the construction SCEC computational and data grid testbeds,
and (5) the development of user interfaces for knowledge-acquisition, code execution, and
visualization.



Pathway 1 (shown in green in Figure 1) is the current methodology of probabilistic seismic
hazard analysis (PSHA), which combines an earthquake forecast model with attenuation
relationships to provide probabilistic estimates of intensity measures. The latter might include
the peak ground acceleration (PGA), peak ground velocity (PGV), or the response spectral
densities at specified frequencies. The earthquake forecast comprises a set of earthquake
scenarios, each described by a magnitude, a location, and the probability that the scenario will
occur by some future date (e.g., a Poisson distribution). The attenuation relationship is a
relatively simple analytical expression that relates each earthquake scenario to the intensity of
shaking (e.g., PGA) at each site of interest; it usually accounts for the local geologic conditions
at each site (e.g., sediment sites tend to shake more than rock sites). The analysis determines the
intensity that will be exceeded at some specified probability over a fixed period of time (e.g.,
PGA with a10% probability of exceedance during the 50-year life span of a building). The
results are often presented as hazard maps, and engineers use these maps to design buildings,
emergency preparedness officials use them for planning purposes, and insurance companies use
them to estimate potential losses.


Pathway 2 (in blue) begins with an earthquake forecast model, but it employs the scenario
events as sources for a physics-based calculation of ground motions. The waves from these
sources are propagated using an anelastic wave model (AWM), and they excite ground motions
at a specified location through a site response model (SRM) that accounts for the near-surface
conditions, such as soil rigidity and layering. The results are vector-valued ground
displacements as a function of time, from which essentially any intensity measure can be
computed. However, in a region like Southern California where the geological structures are
highly three-dimensional, the wavefield calculations must be done for each scenario earthquake
on very dense grids to get the high frequencies of engineering interest (> 1 Hz), and the
computational demands for these simulations can be enormous. One of the principal objectives
of this proposal is to accelerate the use of ground-motion modeling in SHA.


In this first annual report, we discuss the organization, the short-term objectives, and long-
term research plans of the SCEC/ITR Project.
Project Organization
Steering Committee. The Project Steering Committee is chaired by the Principal Investigator, T.
Jordan (USC), and comprises the three Co-P.I.s, C. Kesselman (ISI), J.-B. Minster (SIO), and R.
Moore (SDSC), plus the senior scientists T. Ahern (IRIS), Y. Gil (ISI), and K. Olsen (UCSB).
The Steering Committee is responsible for all aspects of Project oversight, including setting the
research agenda and monitoring results.

Information Architect. The Information Architect acts as the Project Manager and will be
responsible for software integration and interoperability, including integration with other
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2 components of SCEC. This USC-based position is co-supported by the Project and the SCEC
base funding. A nationwide search was conducted and several outstanding candidates were
identified. An offer was made to one of these candidates in April, 2002; he initially accepted the
position but withdrew in June, 2002, when he encountered difficulties in relocating his family to
the Los Angeles area. The search was reopened and finally filled in November, 2002, with the
hiring of Philip J. Maechling as the SCEC Information Architect.


Mr. Maechling received his B.S. in physics from Xavier University in 1983 and worked as a
software engineer in new system development for Hughes Aircraft Co. and TRW, Inc., before
joining the Caltech Seismological Laboratory in 1993. At Caltech, he was the system
development coordinator for the TriNet broadband seismometer network. He left Caltech in
2000 to become a senior software engineer at Cysive Inc. Mr. Maechling will assume the duties
of SCEC Information Architect on December 1, 2002.

Project Teams. The teams that have been organized to conduct the research and development on
specific project elements are described in the next section of this report. A key feature of our
organizational strategy is to involve both geophysicists and computer scientists on each team in
order to facilitate communication and cross-training between these disciplines. We are very
pleased with the degree of cooperation engendered in all of these teams. The Project appears to
have the right mix of expertise among its senior scientists to accomplish its goals.

Education and Outreach. The E&O efforts of this project are being managed by Mark Benthien,
the SCEC Associate Director of Communication, Education, and Outreach. During this first
performance period, the project sponsored the very successful SCEC/ITR Summer Intern
program, which involved 9 undergraduate students and 4 masters students. The efforts of these
interns were focused on the development of a web-enabled, open-source, object-oriented
Community Visualization Environment. A prototype of the system, described in the next
section, was demonstrated at the SCEC Annual Meeting in September, 2002. The University of
Southern California provided $10,000 in additional funds to the intern program, which has
allowed it to be continued into the 2002-2003 academic year. One of the summer interns,
Jeremy Zechar, who will graduate with a B.S. degree in computer science in December, 2002,
will begin as a graduate student in geophysics under the supervision of Professor Jordan in
January, 2003.

Advisory Council. We are in the process of setting up a five-member Advisory Council of
experts external to the project. The Council will advise the Steering Committee on all aspects of
the Project. The Council will meet at least annually, and its written reports will be transmitted
verbatim to the NSF for review. The chair of the Project Advisory Council will also serve as a
member of the SCEC Advisory Council to provide a mechanism for evaluating the coordination
of Project activities with other SCEC efforts.
Project