Geology and Geomorphology Based f0 Model of New England
Earthquake site response studies are needed to estimate ground motions and quantify seismic hazard. Whereas site-specific studies analyze individual locations and compute 1D, 2D or 3D ground response at that location, regional studies integrate many pieces of information to develop a general understanding of a particular geologic unit, or an entire region composed of many geologic units. In this study, a regional f0 model of New England is developed by integrating geologic polygons, categorical subregions, river buffers, distance to coastlines and topographically derived geomorphic parameters. New England is a glaciated terrain and site response is controlled by the sediment thickness and the high impedance contrast between sediments and hard bedrock. f0 derived from HVSR analysis provides a useful tool for regional site response studies because it is inexpensive and easy to collect over large areas, contains both velocity and depth information, and is known to be especially effective in high impedance environments. For this study, we compile 1627 f0 measurements and geospatial proxies (slope, CTI and others) and stitch together a surficial geology map of New England based on existing state-based maps. In addition, we identify five geologic subregions of interest: Connecticut River Valley, Boston Basin, Southern Moraine Terrain, Champlain Sea Sediments and the Maine Coast. The f0 data and predictor variables are explored and general f0 patterns are identified. Our first product is a geology-based f0 map of New England. Within this map, velocity information is added by subregion allowing the computation of sediment thickness (d) and average shear-wave velocity (Vsavg) in the sediments. With these three values, f0, Vsavg and d, Vs30 based site class and other earthquake engineering parameters are estimated. Our second product is a geospatial proxy based f0 map of New England. This map is derived empirically using regression techniques and continuous and categorical geospatial and geologic site response proxies. Both maps provide information on regional trends for site response for New England.
Session: Advances in Geospatial Modeling of Seismic Hazards [Poster]
Type: Poster
Room: Evergreen Ballroom
Date: 4/20/2022
Presentation Time: 08:00 AM Pacific
Presenting Author: Marshall A. Pontrelli
Student Presenter: Yes
Additional Authors
Marshall Pontrelli Presenting Author Corresponding Author marshall.pontrelli@tufts.edu Tufts University |
Laurie Baise laurie.baise@tufts.edu Tufts University |
John Ebel John.edel@bc.edu Boston College |
Stephen Mabee sbmabee@geo.umass.edu University of Massachusetts |
Weiwei Zhan weiwei.zhan@tufts.edu Tufts University |
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Geology and Geomorphology Based f0 Model of New England
Category
Advances in Geospatial Modeling of Seismic Hazards
Description