Some Thoughts on IMW And Opportunity We represent a big area of the ANSS national program Bob Smith Univ. of Utah

What We Are Up Against! $4.1B US, with only $0.2B in the Intermountain West FEMA Annualized Earthquake Loss Estimate (2000) IMW has twice the area of the west coast (lower 48) and some of the highest population growth centers in the entire U.S. We need to just justify a proposal with consensus and as an integrated regional program within a ANSS national scheme.

Historic Seismicity of the Intermountain West Properties: 1. Nucleation at the mid-crustal brittle- ductile transition, 2. 45° to 70° dipping, planar dip- and oblique-slip faulting, 3. Fault-bounded sedimentary basins, 4. Large dynamic stresses and large hanging-wall accelerations. Working Model For Normal-Faulting Earthquakes

What’s Driving Earthquakes Now! GPS velocity field (interpolated) Deviatoric Strain-rate Tensor Field

We are different from California IMW unique earthquake shaking scenarios need normal-fault/basin data that ANSS can provide. (after Archuleta and Smith, 2006) Need S-wave data of fault-bounded valleys for local site effects, attenuation, etc. for dynamic ground shaking models with unexpectedly large PGAs and PGVs.

IMW NEHRP and ANSS Earthquake Research Needs Evaluate site-specific amplification on fault-bounded alluvial valleys and with appropriate stress drops and dynamic stress conditions. Incorporate local site conditions, Vs30, and directivity in hazard assessments and scenarios. Report earthquake catalogs using 3D velocity models. Acquire strong to weak-ground-motions and develop attenuation relationships for extensional regimes. Evaluate stochastic, characteristic, and cluster earthquake recurrence models. Understand the relationship of contemporary deformation to inter-seismic loading and post- seismic relaxation of active faults. Integrate seismic, geologic, and geodetic for time-dependent seismic hazards focusing on broader geographic, including need urban assessments. Take advantage of data acquired by EarthScope arrays, before they are gone! Understand the physics of lithospheric extension and the mechanisms of normal faults.

IMW & USArray Stations

Earthquake Monitoring of the eastern Intermountain West, 2006 Seismic Networks: - Montana Bureau of Mines and Geology - University of Utah Seismograph Stations - Idaho National Engineering and Environmental Lab - USGS Teton Network - United States National Seismic Network - Northern Arizona University

USArray Transportable Array Siting and Recon for the Deployment - Non Reconned - Reconned

A Dense Array USArray Array + Existing Networks, A Dense Array - Non Reconned - Reconned

An Unprecedented Opportunity Integrated Intermountain Earthquake Monitoring An Unprecedented Opportunity - USArray Seismographs - GPS - Regional Seismic Networks

Areas of possible TA adoptions (blue), , and ANSS Expansion (red)

A Partial Solution: Adoption of selected ANSS stations

A Partial Solution: Adoption of selected USArray stations ANSS has up to 80 of 400 existing instruments available and 60 have six channels for FBAs Document by TA resulting from discussions of TA, USGS and NSF being prepared.

Recommendations  Develop a unified plan (patterned after CISN) that documents a consensus of needs for all of ANSS-IMW with integrated recording and archiving.  Highlight the importance of IMW as a key element of the national ANSS network.  Point out the parallel science needs to improve earthquake science and the ANSS network.  Emphasize partnerships that can benefit ANSS with University matching funds and direct support, state funds, EarthScope, USGS, other agencies, etc.  Make explicit plans for new ANSS stations and for USArray adoptions.  Develop data access for non-seismological users: engineering-science and for general educational and outreach.  Catch University faculty are restricted from making direct congressional contacts for lobbying purposes, particularly if funds are already being sought for parallel purposes.

Complimentary GPS Array, ~90 sites GPS Networks: - University of Utah - Plate Boundary Observatory - Basin and Range Geodetic Network - National Geodetic Survey - Regional Networks - PBO Backbone