We present a preliminary point inventory of landslides triggered by Hurricane Helene, which impacted southern Appalachia between September 25–27, 2024. This inventory is a result of a rapid response mapping effort led by the U.S. Geological Survey’s Landslide Assessments, Situational Awareness, and Event Response Research (LASER) project. LASER collaborated with state surveys and landslide researchers to identify landslides and their impacts for situational awareness and emergency response. The area of interest (AOI) for this effort was informed by a preliminary landslide hazard map created for the event (Martinez et al., 2024), and encompasses western North Carolina as well as parts of Tennessee, Virginia, Georgia, and South Carolina. This point inventory contains the following attributes: ‘Source’ and ‘Impact’. The ‘Source’ attribute identifies the data source(s) used to map each landslide. Note that the data sources listed in this attribute refer only to those used for mapping a given landslide; this does not imply that the landslide is absent or undocumented in other unlisted sources. We do not provide any specific information or metadata (e.g., footprint ID, imagery date, hyperlinks, etc.) for the listed source(s) used to map a landslide. The sources used for mapping landslides in this inventory are listed in Table 1. We relied heavily on Sentinel-2 satellite data during the mapping phase and exclusively during the review phase. While Sentinel-2 has a lower spatial resolution (10m) compared to other satellite and aerial sources (ranging from 0.15 to 3m), it is the only dataset with complete mapping AOI coverage and pre- and post-event multi-spectral imagery. The primary Sentinel-2 images used were acquired on August 26, 2024, and September 22, 2024 (pre-event), as well as October 2, 5, 7, 10, and 12, 2024 (post-event). To assist in rapid landslide detection, we derived Normalized Difference Vegetation Index (NDVI) change products using various combinations of the pre- and post-event Sentinel-2 data. NDVI change analysis was instrumental in identifying areas where vegetation loss or damage occurred, thus helping to pinpoint potential landslide activity in this heavily vegetated region. Additionally, red-green-blue (RGB) composite imagery from both pre- and post-event acquisitions was used to validate that NDVI changes were indeed indicative of landslides. Details on these data sources and analysis methods area can be found in Burgi et al. (2024). The data sources listed in the ‘Source’ attribute listed in alphabetical order. The ‘Impact’ attribute indicates the primary impact of a landslide. The options for the impact attribute are listed in Table 2. A landslide is deemed to have an impact if it appears to intersect with river(s) (including streams and creeks), road(s), building(s), or other human-modified land or infrastructure (e.g., bridges, railroads, powerlines, trails, agricultural fields, lawns, etc.) Impact was determined to the best of a mapper’s ability with the available data and at the time that the imagery was acquired. Many landslides had multiple impacts; however, in most cases, a primary impact could be identified. For example, many landslides appeared to severely impact a road and continue to fail into a nearby river, with no visible impact on the river. In this case, the primary impact would be “road”. If a landslide appeared to have multiple and equally significant impacts, it was classified as “various”. We do not report the number of impacts; for example, a landslide with a “building” Impact may have impacted more than one building. Emergency response landslide mapping efforts took place between September 28 to October 23, 2024. All landslides were mapped with a single point, irrespective of size or impact. Given the urgency of providing situational awareness for emergency response, landslide points were placed at the location of greatest visible impact, such as buildings, roads, and rivers, rather

Here we present an inventory of remotely and field-observed landslides triggered by 2019-2020 Puerto Rico earthquake sequence. The inventory was mapped using pre- and post-event satellite imagery (PR_landslide_inventory_imagery.csv), an extensive collection of field observations (https://doi.org/10.5066/P96QNFMB) and using pre-earthquake lidar as guidance for mapping polygons with more precise locations and geometries (2015 - 2017 USGS Lidar DEM: Puerto Rico dataset). The inventory consists of a shapefile of 309 polygons (PR_landslide_inventory_pts.shp) outlining the source area and deposits together. It also includes a point inventory (PR_landslide_inventory_pts.shp) marking 170 individual displaced boulders that were outside of areas that could be mapped as polygons and 28 points that indicate rock falls for which we did not have sufficient information from imagery or photos to map as polygons. The individual boulders and rock fall points are differentiated from each other by the “Type” attribute field. Most individual boulders were mapped from imagery, while most rock fall points were mapped based on field observations alone (e.g. notes about occurrences without photos) because they were not readily visible in imagery or captured in photos. Most landslides were triggered initially by the largest earthquake, a M6.4 on 7 Jan 2020, and we include an attribute named “Trigger” to differentiate whether we think each landslide was triggered during the mainshock, an aftershock, a foreshock, or whether the trigger is unknown given the data available to us. The trigger attribute field is uncertain because in some instances, smaller rock falls and rock fall areas that did not completely strip the vegetation from the slope were at times obscured by vegetation immediately post-earthquake and were only visible in later satellite imagery once some vegetation began to die. These rock fall runout areas were mapped on imagery from several months after the earthquake (10 April 2020) because their spatial extent was far easier to see once the vegetation had died back sufficiently. We did not have sufficient information on many landslides to classify landslide types accurately, so this is not included as an attribute, however the vast majority were interpreted as rock falls. Only three landslides that we documented occurred solely in soil. More than a third of the rock falls we mapped occurred on artificially altered slopes like road cuts (noted by the attribute field “Cutslope”). The “Massive” attribute indicates whether the landslide appeared to involve a detachment of most of the source area at once, as observed in field photos where possible and imagery where photos were not available. Massive is set to false if the slope failure involves many individual rock detachments while other parts of the source area remained intact. Some large polygons actually represent runout areas over which many individual rocks rolled without involving failure of the entire face of the source area (Massive=False) and should not be interpreted as a single large landslide. While lateral spreading was triggered by this earthquake sequence, we do not include it in this inventory and instead group it with the liquefaction inventory for this event (https://doi.org/10.5066/P9JEN3H2).

Here we present an inventory of remotely and field-observed landslides triggered by 2019-2020 Puerto Rico earthquake sequence. The inventory was mapped using pre- and post-event satellite imagery (PR_landslide_inventory_imagery.csv), an extensive collection of field observations (https://doi.org/10.5066/P96QNFMB) and using pre-earthquake lidar as guidance for mapping polygons with more precise locations and geometries (2015 - 2017 USGS Lidar DEM: Puerto Rico dataset). The inventory consists of a shapefile of 309 polygons (PR_landslide_inventory_pts.shp) outlining the source area and deposits together. It also includes a point inventory (PR_landslide_inventory_pts.shp) marking 170 individual displaced boulders that were outside of areas that could be mapped as polygons and 28 points that indicate rock falls for which we did not have sufficient information from imagery or photos to map as polygons. The individual boulders and rock fall points are differentiated from each other by the “Type” attribute field. Most individual boulders were mapped from imagery, while most rock fall points were mapped based on field observations alone (e.g. notes about occurrences without photos) because they were not readily visible in imagery or captured in photos. Most landslides were triggered initially by the largest earthquake, a M6.4 on 7 Jan 2020, and we include an attribute named “Trigger” to differentiate whether we think each landslide was triggered during the mainshock, an aftershock, a foreshock, or whether the trigger is unknown given the data available to us. The trigger attribute field is uncertain because in some instances, smaller rock falls and rock fall areas that did not completely strip the vegetation from the slope were at times obscured by vegetation immediately post-earthquake and were only visible in later satellite imagery once some vegetation began to die. These rock fall runout areas were mapped on imagery from several months after the earthquake (10 April 2020) because their spatial extent was far easier to see once the vegetation had died back sufficiently. We did not have sufficient information on many landslides to classify landslide types accurately, so this is not included as an attribute, however the vast majority were interpreted as rock falls. Only three landslides that we documented occurred solely in soil. More than a third of the rock falls we mapped occurred on artificially altered slopes like road cuts (noted by the attribute field “Cutslope”). The “Massive” attribute indicates whether the landslide appeared to involve a detachment of most of the source area at once, as observed in field photos where possible and imagery where photos were not available. Massive is set to false if the slope failure involves many individual rock detachments while other parts of the source area remained intact. Some large polygons actually represent runout areas over which many individual rocks rolled without involving failure of the entire face of the source area (Massive=False) and should not be interpreted as a single large landslide. While lateral spreading was triggered by this earthquake sequence, we do not include it in this inventory and instead group it with the liquefaction inventory for this event (https://doi.org/10.5066/P9JEN3H2).

This inventory was originally created by Harp and others (2016) describing the landslides triggered by the M 7.0 Haiti earthquake that occurred on 12 January 2010 at 21:53:10 UTC. Care should be taken when comparing with other inventories because different authors use different mapping techniques. This inventory also could be associated with other earthquakes such as aftershocks or triggered events. Please check the author methods summary and the original data source for more information on these details and to confirm the viability of this inventory for your specific use. With the exception of the data from USGS sources, the inventory data and associated metadata were not acquired by the U.S. Geological Survey (USGS) and thus have not been reviewed for accuracy and completeness by the USGS. They are presented as part of this data series for convenience of the user only, as part of an effort to make published ground-failure inventories more accessible from a single aggregated site. No warranty, expressed or implied, is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

This inventory was originally created by Harp and others (2016) describing the landslides triggered by the M 7.0 Haiti earthquake that occurred on 12 January 2010 at 21:53:10 UTC. Care should be taken when comparing with other inventories because different authors use different mapping techniques. This inventory also could be associated with other earthquakes such as aftershocks or triggered events. Please check the author methods summary and the original data source for more information on these details and to confirm the viability of this inventory for your specific use. With the exception of the data from USGS sources, the inventory data and associated metadata were not acquired by the U.S. Geological Survey (USGS) and thus have not been reviewed for accuracy and completeness by the USGS. They are presented as part of this data series for convenience of the user only, as part of an effort to make published ground-failure inventories more accessible from a single aggregated site. No warranty, expressed or implied, is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

This inventory was originally created by Harp and others (1984) describing the landslides triggered by a sequence of earthquakes, with the largest being the M 6.5 Mammoth Lakes, California earthquake that occurred on 25 May 1980 at 19:44:50 UTC. Care should be taken when comparing with other inventories because different authors use different mapping techniques. This inventory includes landslides triggered by a sequence of earthquakes rather than a single mainshock. Please check the author methods summary and the original data source for more information on these details and to confirm the viability of this inventory for your specific use. With the exception of the data from USGS sources, the inventory data and associated metadata were not acquired by the U.S. Geological Survey (USGS) and thus have not been reviewed for accuracy and completeness by the USGS. They are presented as part of this data series for convenience of the user only, as part of an effort to make published ground-failure inventories more accessible from a single aggregated site. No warranty, expressed or implied, is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

This inventory was originally created by Harp and others (1984) describing the landslides triggered by a sequence of earthquakes, with the largest being the M 6.5 Mammoth Lakes, California earthquake that occurred on 25 May 1980 at 19:44:50 UTC. Care should be taken when comparing with other inventories because different authors use different mapping techniques. This inventory includes landslides triggered by a sequence of earthquakes rather than a single mainshock. Please check the author methods summary and the original data source for more information on these details and to confirm the viability of this inventory for your specific use. With the exception of the data from USGS sources, the inventory data and associated metadata were not acquired by the U.S. Geological Survey (USGS) and thus have not been reviewed for accuracy and completeness by the USGS. They are presented as part of this data series for convenience of the user only, as part of an effort to make published ground-failure inventories more accessible from a single aggregated site. No warranty, expressed or implied, is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

This inventory was originally created by Keefer and Manson (1998) describing the landslides triggered by the M 6.9 Loma Prieta, California earthquake that occurred on 18 October 1989 at 00:04:15 UTC. Care should be taken when comparing with other inventories because different authors use different mapping techniques. This inventory also could be associated with other earthquakes such as aftershocks or triggered events. Please check the author methods summary and the original data source for more information on these details and to confirm the viability of this inventory for your specific use. With the exception of the data from USGS sources, the inventory data and associated metadata were not acquired by the U.S. Geological Survey (USGS) and thus have not been reviewed for accuracy and completeness by the USGS. They are presented as part of this data series for convenience of the user only, as part of an effort to make published ground-failure inventories more accessible from a single aggregated site. No warranty, expressed or implied, is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

This inventory was originally created by Keefer and Manson (1998) describing the landslides triggered by the M 6.9 Loma Prieta, California earthquake that occurred on 18 October 1989 at 00:04:15 UTC. Care should be taken when comparing with other inventories because different authors use different mapping techniques. This inventory also could be associated with other earthquakes such as aftershocks or triggered events. Please check the author methods summary and the original data source for more information on these details and to confirm the viability of this inventory for your specific use. With the exception of the data from USGS sources, the inventory data and associated metadata were not acquired by the U.S. Geological Survey (USGS) and thus have not been reviewed for accuracy and completeness by the USGS. They are presented as part of this data series for convenience of the user only, as part of an effort to make published ground-failure inventories more accessible from a single aggregated site. No warranty, expressed or implied, is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

This inventory was originally created by Marc and others (2016) describing the landslides triggered by the M 7.6 Valle de la Estrella, Costa Rica earthquake that occurred on 22 April 1991 at 21:56:51 UTC. Care should be taken when comparing with other inventories because different authors use different mapping techniques. This inventory also could be associated with other earthquakes such as aftershocks or triggered events. Please check the author methods summary and the original data source for more information on these details and to confirm the viability of this inventory for your specific use. With the exception of the data from USGS sources, the inventory data and associated metadata were not acquired by the U.S. Geological Survey (USGS) and thus have not been reviewed for accuracy and completeness by the USGS. They are presented as part of this data series for convenience of the user only, as part of an effort to make published ground-failure inventories more accessible from a single aggregated site. No warranty, expressed or implied, is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.