Brian F. Atwater 20231027 tabular digital data This data release updates and enlarges on an electronic supplement to a journal article in https://doi.org/10.1130/GES01356.1. The release is intended to support a monograph in preparation in 2023, to be submitted for publication in the Smithsonian series Atoll Research Bulletin. https://doi.org/10.5066/P9TLLBOC This part of the data release provides an updated georeferenced guide to the main unit of Holocene sand ascribed to a sea flood on Anegada. Much of the data was previously summarized in Figure A4 of https://doi.org/10.1130/GES01356.1 . Plotted here, on the accompanying map, are all 573 localities in the updated compilation <Sand_main.csv>—nearly half of which do not provide much if any evidence for marine inundation. The main attribute of each locality is one of four summary categories: Pervasive—Sand covers more than 3/4 of area and typically thicker than 5 cm (132 localities). Patchy—Sand covers less than 3/4 of area and typically thinner than 5 cm (185 localities). Scant—Called “Sand scarce or absent” in https://doi.org/10.1130/GES01356.1 (256 localities). Pleistocene—Sand grains evidently weathered from Pleistocene limestone (23 localities). The sand, particularly where pervasive, commonly accompanies coral erratics and anomalous limestone clasts. Where patchy it extends farther inland than they do. Locally this mapping is ambiguous. Some of the sand has probably been redistributed by wind. The sand designated Pleistocene includes, in a correction, 8 sites mistakenly interpreted in https://doi.org/10.1130/GES01356.1 as Holocene marine sand. This data release has the overall purpose of supporting assessments of hazards from unusually large tsunamis generated in the northeast Caribbean. An immediate application is to support a manuscript, in preparation in 2023, that asks whether the precolonial sea flood terminated precolonial conch fishing from Anegada. For use in testing simulations storms and tsunamis, the sand mapped as "pervasive" indicates marine inundation more reliably than does sand mapped as "patchy," and sand mapped as "scant" provides insufficient field evidence for having been deposited by a sea flood. The distribution of sand classified in https://doi.org/10.1130/GES01356.1 as "pervasive" and "patchy" was used in Figure 11 of https://doi.org/10.1016/j.earscirev.2022.104018 to test appraise a posited tsunami source. 20080319 20170315 observed Complete None planned Southeast Anegada, Caribbean Sea -64.37440 -64.27260 18.74810 18.69100 ISO 19115 Topic Category geoscientificInformation farming Marine Realms Information Bank (MRIB) keywords corals tsunamis USGS Thesaurus hurricanes sand USGS Metadata Identifier USGS:6492a093d34ef77fcb009bd7 Common geographic areas British Virgin Islands Caribbean Sea None. Please see 'Distribution Info' for details. No issues with privacy or intellectual property. When using individual datasets, please see metadata and "Comments" columns to consider limitations and appropriate uses. Brian F. Atwater U.S. Geological Survey Scientist Emeritus mailing

University of Washington ESS 351310

Seattle WA 98195 206-553-2927 atwater@usgs.gov FIELD OBSERVERS identified in data set, listed alphabetically: Brian Atwater, Anna Lisa Cescon, Robert Halley, Carlos Nuñez, Jean Roger, Alejandra Rodríguez, Yuki Sawai, Michaela Spiske, Uri Ten Brink, Martitia Tuttle. EXTERNAL FUNDING: U.S. Nuclear Regulatory Commission, NRC Job CodeV6166. OTHER: Permissions were arranged by the Department of Disaster Management of the Government of the British Virgin Islands. Residents of Anegada, particularly Harella Georges, extended many courtesies to the field parties. Quantum Spatial and Wayne Wright made the terrestrial and shallow-water lidar surveys, respectively, with geodetic help from Alberto López-Venegas. Craig Weaver arranged for much of the financial support for the terrestrial survey. Brian Andrews and Harvey Greenberg merged lidar data. Operating system and software: Windows 10; tables extracted to Excel from ArcMap 10.8; Office 365 File names and sizes are detailed in child items Brian F. Atwater Uri S. ten Brink Anna Lisa Cescon Nathalie Feuillet Zamara Fuentes Robert B. Halley Carlos Nuñez Eduard G. Reinhardt Jean H. Roger Yuki Sawai Michaela Spiske Martitia P. Tuttle Yong Wei Jennifer Weil-Accardo 20170317 publication Geosphere vol. 13, issue 2 n/a Geological Society of America ppg. 301-368 Open-access Data repository with the 2017 Geosphere article contains previous compilations from field work through 2016. Not included in the GSA data repository are findings from field work in 2017 nor, with offshore modern conch heaps, in 2018, nor 25 radiocarbon ages obtained in 2017 or later https://doi.org/10.1130/GES01356.1 Brian F. Atwater Uri S. ten Brink Mark Buckley Robert S. Halley Bruce E. Jaffe Alberto M. López-Venegas Eduard G. Reinhardt Maritia P. Tuttle Steve Watt Yong Wei 20101026 publication Natural Hazards vol. 63, issue 1 n/a Springer Science and Business Media LLC ppg. 51-84 Open-access In include Electronic Supplementary Material (ESM) https://doi.org/10.1007/s11069-010-9622-6 B. F. Atwater Z. Fuentes R. B. Halley U. S. Ten Brink M. P. Tuttle 20140307 publication Advances in Geosciences vol. 38 n/a Copernicus GmbH ppg. 21-30 Open access https://doi.org/10.5194/adgeo-38-21-2014 Alexandra M Fredericks Uri S Brink Brian F Atwater Christine Kranenburg David B Nagle 2016 dataset https://www.sciencebase.gov U.S. Geological Survey Terrestrial lidar and, north of the island, shallow-water lidar https://doi.org/10.5066/F7GM85F3 Eduard G. Reinhardt Jessica Pilarczyk Alyson Brown 20110204 publication Natural Hazards vol. 63, issue 1 n/a Springer Science and Business Media LLC ppg. 101-117 Data source on sand-and-shell sheet deposited ca. 1650 to 1800 C.E. https://doi.org/10.1007/s11069-011-9730-y Steve Watt Mark Buckley Bruce Jaffe 20110531 publication Natural Hazards vol. 63, issue 1 n/a Springer Science and Business Media LLC ppg. 119-131 Data source on limestone boulder fields near Bumber Well Pond https://doi.org/10.1007/s11069-011-9848-y Hira Ashfaq Lodhi 2020 publication Karachi NED University of Engineering and Technology Unpublished Ph.D. thesis, 141 p. Contains a chapter on modeling of transport of Anegadan limestone boulders by simulated tsunamis from the normal faulting and thrust faulting in the Puerto Rico Trench L. Cordrie N. Feuillet A. Gailler M. Biguenet E. Chaumillon P. Sabatier 202205 publication Earth-Science Reviews vol. 228 n/a Elsevier BV ppg. 104018 https://doi.org/10.1016/j.earscirev.2022.104018 Point locations by hand-held GPS. In comparisons among users of different devices, coordinates rarely differed by more than ten meters. The compiled data contains a correction to localities on central Anegada, on limestone cays south of Red Pond. In this area, on the basis of reconnaissance in 2016, sand on those cays had been interpreted as evidence that a pre-Columbian sea flood carried sand to cay elevations as high as 3.9 m (https://doi.org/10.1130/GES01356.1, their Table 3, profile B-B’, p. 320). Further examination in 2017 showed that the sand was instead of local provenance, derived from weathering of Pleistocene deposits and concentrated by runoff from land cleared and furrowed for 19th-century farming. Consistency was difficult to achieve in the field in categorizing sand into mappable geological units. Grains weathered from Pleistocene limestone presented one of the problems, illustrated in the comments on attribute accuracy. Another problem was reworking by wind—a process that may have been particularly effective after the inferred sea flood damaged or removed vegetation. The mapping is least complete on the eastern third of the island. Vegetation and walking distances deterred sand mapping in those areas. For coordinates from hand-held GPS, spurious UTM coordinates—in most cases, those misread in the field or typed incorrectly into a spreadsheet—were detected by plotting on georeferenced airphotos and on lidar imagery. According to the lidar data release (https://doi.org/10.5066/F7GM85F3), "WSI/Quantum Spatial reports that the Fundamental Vertical Accuracy (FVA) was computed by comparing the known Real Time Kinematic (RTK) ground control point data collected on open, bare earth surfaces with level slope to the triangulated ground surface generated by the LiDAR points. They report that the root mean square error (RMSE) was computed to be 0.021 m." Initial field work in 2008, 2009, and 2011, mainly in western Anegada. Eastern field work chiefly in 2015, 2016, and 2017. The mapping in all cases targeted coral erratics and anomalous limestone clasts in addition to sand Locations by hand-held GPS. Before 2015 these points were plotted on vertical airphotos taken 1969, 2002, and 2005. Lidar topography and bathymetry, surveyed in 2014, in use beginning in 2015. Examples: base maps in https://doi.org/10.1130/GES01356.1 and Sand unit introduced in https://doi.org/10.1130/GES01356.1, with map summary in that report's Figure A4 The "Process Date" refers in this instance to the most recent editing of the datasets, including their csv files and shapefiles. 20230618 Vector Entity point 573 Universal Transverse Mercator 20 0.9996 -63.0 0.0 500000.0 0.0 coordinate pair 0.6096 0.6096 meters WGS_1984 WGS 84 6378137.0 298.257223563 Sand_main.csv Comma Separated Value (CSV) file containing data. Producer Defined Easting Horizontal coordinate in meters, WGS 1984 Complex UTM Zone 20, by hand-held Producer Defined 355069 365849 Northing Horizontal coordinate in meters, WGS 1984 Complex UTM Zone 20, by hand-held Producer Defined 2067193 2073433 Elev_m Elevation, in meters above a datum near mean sea level. Extracted in GIS from lidar digital elevation model Producer Defined -0.3 6.4 Area Anegada place names spelled out; directional modifiers abbreviated Producer Defined << empty cell >> No Data Producer defined Anegada place names spelled out; directional modifiers abbreviated Site_ID Site designation in field notes Producer Defined << empty cell >> No Data Producer defined Site designation in field notes Notes Observer or observers who recorded field evidence, GPS position, or both Producer Defined Observer or observers who recorded field evidence, GPS position, or both Date Day and month of field observation. Initial observation, later observation or sampling, or both Producer Defined Day and month of field observation. Initial observation, later observation or sampling, or both Year Year of field observation. Initial observation, later observation or sampling, or both Producer Defined 2008 2017 Pervasive Holocene sand covers 3/4 of area and is typically thicker than 5 cm Producer Defined 0 FALSE Producer defined 1 TRUE Producer defined Patchy Holocene sand is evident but covers less than 3/4 of area and is typically less than 5 cm thick, but Producer Defined 0 FALSE Producer defined 1 TRUE Producer defined Scant Holocene sand is scarce or absent Producer Defined 0 FALSE Producer defined 1 TRUE Producer defined Pleist Sand is evident but was probably derived in vicinity by weathering of Pleistocene limestone Producer Defined 1 TRUE Producer defined 0 FALSE Producer defined Correction Sand category changed from that reported in https://doi.org/10.1130/GES01356.1 Producer Defined 2 Changed to Pleist Producer defined 1 Changed to Scant Producer defined 0 No change Producer defined Thick_cm Sand thickness, in centimeters Producer Defined << empty cell >> No Data Producer defined 1 55 Thickrange Sand thickness as range in centimeters Producer Defined << empty cell >> No Data Producer defined Sand thickness as range in centimeters Min_thick Minimum sand thickness, in centimeters Producer Defined << empty cell >> No Data Producer defined 1 30 Eolian Sand noticeably thickened by wind Producer Defined 0 FALSE Producer defined 1 TRUE Producer defined Comments Comments Producer Defined << empty cell >> No Data Producer defined Comments This part of the data release provides an updated georeferenced guide to the main unit of Holocene sand ascribed to a sea flood on Anegada. Much of the data was previously summarized in Figure A4 of https://doi.org/10.1130/GES01356.1 . Plotted here, on the accompanying map, are all 573 localities in the updated compilation Sand_main. At nearly half of these localities the sand is too scarce or ambiguous to provide much if any evidence for marine inundation. The main attribute of each locality is one of four summary categories: Pervasive -- Sand covers more than 3/4 of area and typically thicker than 5 cm (132 localities). Patchy -- Sand covers less than 3/4 of area and typically thinner than 5 cm (185 localities). Scant -- Called “Sand scarce or absent” in https://doi.org/10.1130/GES01356.1 (256 localities). Pleistocene -- Sand grains evidently weathered from Pleistocene limestone (23 localities). The sand, particularly where pervasive, commonly accompanies coral erratics and anomalous limestone clasts. Where patchy it extends farther inland than they do. Locally this mapping is ambiguous. Some of the sand has probably been redistributed by wind. The sand designated Pleistocene includes, in a correction, 8 sites mistakenly interpreted in https://doi.org/10.1130/GES01356.1 as Holocene marine sand. For use in testing simulations storms and tsunamis, the sand mapped as "pervasive" indicates marine inundation more reliably than does sand mapped as "patchy," and sand mapped as "scant" provides insufficient field evidence for having been deposited by a sea flood. Presence and absence of a widespread unit of Holocene marine sand observed in 2008 to 2017 in tsunami-hazard assessments on Anegada, British Virgin Islands GS ScienceBase U.S. Geological Survey mailing address

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Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/xxxxxxxx None 20231027 Brian F. Atwater U.S. Geological Survey Scientist Emeritus mailing

University of Washington ESS 351310

Seattle WA 98195 206-553-2927 atwater@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999