COLLAPSIBLE SOIL SUSCEPTIBILITY MAP FOR NEW MEXICO (1:750,000) BASED ON MULTIPLE PROXIES New Mexico Bureau of Geology and Mineral Resources Open-File Report OFR-593 Prepared by: Alex J. Rinehart, Hydrogeologist Colin T. Cikoski, Geologist Mark M. Mansell, GIS Analyst David W. Love, Principal Senior Environmental Geologist (Emeritus) New Mexico Bureau of Geology and Mineral Resources New Mexico Tech, 801 Leroy Place Socorro, NM 87801 Prepared for New Mexico Department of Homeland Security and Emergency Management 13 Bataan Blvd. Santa Fe, NM 87508 New Mexico Hazard Mitigation Assistance Program Sub-grant FEMA-4152-DR-NM-020 December, 2017 http://geoinfo.nmt.edu/publications/openfile/details.cfml?Volume=593 This project maps the susceptibility of subsidence due to collapsible, or hydrocompactive soils across New Mexico on a 500 m resolution grid based on multiple proxies. Collapsible or hydrocompactive soils are formed in loose, poorly sorted, unconsolidated sediment, generally rapidly deposited alluvium or eolian materials. When wetted and loaded, these deposits can consolidate by factors of up to 20%, meaning that a 10 ft deposit could consolidate by 2 ft. Because the deposits are generally only found after structures have been built on them and significant run-on has occurred, mapping susceptibilities require a non-statistical approach--known locations are too few to be relevant. In this study, we mapped known locations around the state, and then used a spatial weighted average, or overlay, method to estimate susceptibility based on mulitple proxies. Proxies were weighted based on their reliability and strength of correlation; usually, textural information was weighted the highest while indirect proxies such as climate and land-use were weighted lowest. Four final maps were produced: total susceptibility (Plate 1); average quality, or weighting (Plate 2); number of proxies (Plate 3); and known locations (see report and appendix). When assessing hydrocompaction susceptibility of a site, the total susceptibility should be considered in the context of the average quality and number of proxies. Lower quality and few proxies imply that the estimates are unreliable. Qualitative break are defined in the report. We provide three sets of electronic products: 1) PDFs of the report and the associated plates. 2) a compilation of geodatabases with a new Koeppen-Geiger climate zone map for New Mexico, inputted rasters of proxies susceptibility, proxy quality, known collapse features, and the final susceptibility, mean quality and number of proxies used. 3) map packages for page and plate sized maps of total susceptibility, mean quality, number of proxies and known collapse locales. (2) and (3) form the electronic supplement for the report. The Python 2.7 scripts used to generate the final product are available on request (alex.rinehart@nmt.edu or colin.cikoski@nmt.edu). ----------------------------------------------------------------------- SYSTEM REQUIREMENTS: A computer capable of running some or all of the following software: Adobe Acrobat (v.9 or later) to view the Plates (*.pdf) -- freeware: http://get.adobe.com/reader ArcGIS (v. 10.0 or later) to open GIS projects/data (*.mpk) ArcReader (v. 10) to view GIS data contained in the map packages -- freeware: http://www.esri.com/software/arcgis/arcreader -----------------------------------------------------------------------