Field observations of landslides and related materials following Hurricane Maria, Puerto Rico

During September 2017, Hurricane Maria caused widespread landsliding throughout mountainous regions of Puerto Rico, with more than 71,000 landslides being subsequently identified from aerial imagery (Hughes et al., 2019). Most landslides apparently mobilized as debris flows and occurred within soil (unconsolidated material overlying saprolite and bedrock) and saprolite overlying less-weathered rock (e.g., Bessette-Kirton et al., 2019a). To better understand the characteristics of Maria-triggered landslides, debris flows, and materials in which landslides occurred, we performed reconnaissance-level studies of 118 landslides, 46 soil exposures generally within landslide scars, 24 saprolite exposures, and 37 rock exposures. Results from these studies are provided herein. Landslides studied were mostly selected from aerial imagery collected between 9-15 October 2017 (Quantum Spatial, Inc., 2017), with emphasis placed on four study areas where landslides were particularly numerous, and which were previously studied (Bessette-Kirton et al., 2019b) using aerial imagery and lidar data. However, we also selected landslides for field study that were spread across the mountainous parts of the main island of Puerto Rico, and which occurred in geological formations in which Maria-induced landslides were numerous. Finally, we selected landslides for field study that were relatively easily accessible from roads, although we attempted to mostly evaluate landslides that did not have clear association with roadway construction or drainage. However, a previous study found that landslides in Puerto Rico are approximately five times more likely near roads compared to away from roads (Larsen and Parks, 1997). Field studies were performed sporadically between June 2018 and March 2022. � Data provided with this release are in the form of a file geodatabase developed using ESRI ArcGIS and which comprises four point feature classes; Soil_Descriptions, Saprolite_Descriptions, Rock_Descriptions, and Source_Areas, with the latter describing locations from which landslides initiated. Measurements of landslide location and dimensions were made in the field using tape measures, laser rangefinders, hand levels, clinometers, pocket transits, geological compasses, and positioning systems on mobile devices (that is, cellular telephones, tablets) that utilize GPS techniques and distance from cellular antennas. Unconfined compressive strength and undrained shear strength under field conditions were approximated for some materials using hand penetrometers and hand vane-shear devices, respectively, with values provided in Consistency/Compactness (unconfined compressive strength) and Notes (undrained shear strength) fields. Soil and saprolite colors were visually estimated using Munsell color charts. Data were collected in the field on mobile devices running ESRI ArcGIS Collector software and subsequently compiled using ArcGIS desktop software. Photographs were collected of many (but not all) features, and these are provided also in the geodatabase. The following paragraphs describe the attributes of each of the four point feature classes. Additional information is provided in the accompanying metadata file. � Soil_Descriptions OBJECTID ? Unique number assigned by software to identify each point observation. � Shape ? Type of feature, in all cases ?point.? � Soil Type ? Visually and manually estimated primary soil type modified by soil types present in lesser amounts, with soil types generally of ?clay,? ?silt,? ?sand,? and ?gravel.? ?Clay? consists of particles 0.002 mm diameter and finer, ?silt? consists of particles 0.002 mm - 0.075 mm diameter, ?sand? consists of particles 0.075 mm - 4.75 mm diameter, and ?gravel? consists of particles 4.75 mm - 75 mm diameter. Secondary soil type may modify primary type (for example, ?silty clay?) if more than 30% of the secondary type is present. Non-primary soil type content also may be described as ?trace? if 1% - 10% is present, ?little? if 10% - 20% is present, ?some? if 20% - 35% is present, and ?and? if 35% - 50% is present. � Munsell Color ? Visually estimated from hand specimens at field moisture content using Munsell color charts. � Field Moisture ? Increasing wetness from ?dry? (powders or doesn?t change color when warmed) to ?moist? (can be rolled into a thread 1/8? in diameter or changes color when warmed) to ?wet? (soft and sticky or holds a molded shape) to ?saturated? (freely drains water). � Plasticity ? Estimated from specimens at field moisture content or higher, with ?non-plastic,? ?slightly plastic,? ?moderately plastic,? ?plastic,? and ?highly plastic? representing the ease with which soil could be rolled into 1/8-inch-diameter threads, with ease increasing toward ?highly plastic? and decreasing toward ?non-plastic.? � Field Dry Strength ? Generally estimated from specimens at field moisture content or lower and ranging from ?none? or ?very little? (crumbles when handled) to ?slight? (can be broken easily) to ?medium? (can be broken with some effort) to ?high? (can be broken with great effort but not powdered) to ?very high? (cannot be broken or powdered using finger pressure). � Cementation ? Estimated generally from silty, sandy, and gravelly field specimens as ?none,? ?weak? (breaks with finger pressure), ?moderate? (cannot be broken with fingers but can be with hammer), or ?strong? (breaks with effort using hammer). � Structure ? Description of any structure identified, such as fracturing, bedding, slickensides, crumb, etc. � Consistency/Compactness ? Estimated from specimens at field moisture content, with some estimates provided quantitatively from hand penetrometer measurements in kg/cm2. For clay, values increase from ?very soft? (squeezes between fingers when hand is closed; 0-0.25 kg/cm2) to ?soft? (easily molded by fingers; 0.25-0.5 kg/cm2) to ?medium stiff? (molded by strong finger pressure; 0.5-1.0 kg/cm2) to ?stiff? (dented by strong finger pressure; 1.0-2.0 kg/cm2) to ?very stiff? (slightly dented by strong finger pressure; 2.0-4.0 kg/cm2) to ?hard? (slightly dented by pencil point; >4.0 kg/cm2). For silt and sand, values increase from ?very loose? (squeezes between fingers when hand is closed; 0-0.25 kg/cm2) to ?loose? (molded by fingers; 0.25-0.75 kg/cm2) to ?medium dense? (dented by strong finger pressure; 0.75-2.0 kg/cm2) to ?dense? (slightly dented by strong finger pressure; 2.0-4.0 kg/cm2) to ?very dense? (slightly dented by pencil point; >4.0 kg/cm2). � Particle Description ? General descriptions of the particle size distribution and of particles themselves. � Notes ? Any notes that the recorder thought were pertinent. � GlobalID ? Unique identifier assigned by software during geodatabase formation. � Saprolite_Descriptions OBJECTID ? Unique number assigned by software to identify each point observation. � Shape ? Type of feature, in all cases ?point.? � Soil Type ? Visually and manually estimated primary soil type modified by soil types present in lesser amounts, with soil types generally of ?clay,? ?silt,? ?sand,? and ?gravel.? ?Clay? consists of particles 0.002 mm diameter and finer, ?silt? consists of particles 0.002 mm - 0.075 mm diameter, ?sand? consists of particles 0.075 mm - 4.75 mm diameter, and ?gravel? consists of particles 4.75 mm - 75 mm diameter. Secondary soil type may modify primary type (for example, ?silty clay?) if more than 30% of the secondary type is present. Non-primary soil type content also may be described as ?trace? if 1% - 10% is present, ?little? if 10% - 20% is present, ?some? if 20% - 35% is present, and ?and? if 35% - 50% is present. � Munsell Color ? Visually estimated from hand specimens at field moisture content using Munsell color charts. � Field Moisture ? Increasing wetness from ?dry? (powders or doesn?t change color when warmed) to ?moist? (can be rolled into a thread 1/8? in diameter or changes color when warmed) to ?wet? (soft and sticky or holds a molded shape) to ?saturated? (freely drains water). � Plasticity ? Estimated from specimens at field moisture content or higher, with ?non-plastic,? ?slightly plastic,? ?moderately plastic,? ?plastic,? and ?highly plastic? representing the ease with which soil could be rolled into 1/8-inch-diameter threads, with ease increasing toward ?highly plastic? and decreasing toward ?non-plastic.? � Field Dry Strength ? Estimated from hand specimens at field moisture content or lower and ranging from ?plastic? (easily molded) to ?friable? (crumbles with finger pressure) to ?weak? (crumbles under light hammer blows) to ?moderate? (withstands several firm hammer blows) to ?strong? (withstands heavy, ringing hammer blows) to ?very strong? (only dust produced by any hammer blow). � Cementation ? Estimated generally from silty, sandy, and gravelly field specimens as ?weak? (breaks with finger pressure), ?moderate? (cannot be broken with fingers but can be with hammer), or ?strong? (breaks with effort using hammer). � Structure ? Description of any structure identified, such as fracturing, bedding, slickensides, crumb, etc. � Consistency/Compactness ? Estimated from specimens at field moisture content, with some estimates provided quantitatively from hand penetrometer measurements in kg/cm2. For clay, values increase from ?very soft? (squeezes between fingers when hand is closed; 0-0.25 kg/cm2) to ?soft? (easily molded by fingers; 0.25-0.5 kg/cm2) to ?medium stiff? (molded by strong finger pressure; 0.5-1.0 kg/cm2) to ?stiff? (dented by strong finger pressure; 1.0-2.0 kg/cm2) to ?very stiff? (slightly dented by strong finger pressure; 2.0-4.0 kg/cm2) to ?hard? (slightly dented by pencil point; >4.0 kg/cm2). For silt and sand, values increase from ?very loose? (squeezes between fingers when hand is closed; 0-0.25 kg/cm2) to ?loose? (molded by fingers; 0.25-0.75 kg/cm2) to ?medium dense? (dented by strong finger pressure; 0.75-2.0 kg/cm2) to ?dense? (slightly dented by strong finger pressure; 2.0-4.0 kg/cm2) to ?very dense? (slightly dented by pencil point; >4.0 kg/cm2). � Particle Description ? General descriptions of the particle size distribution and of particles themselves. � Parent Rock Type ? Estimated during field evaluation. � Bedding Spacing, Orientation - Estimated and measured during field evaluation. � Fracture Spacing, Orientation - Estimated and measured during field evaluation. � Fracture Condition ? Estimated during field evaluation. � Hardness ? Estimated from hand specimens and ranging from ?soft? (moldable) to ?friable? (crumbles or powders) to ?low? (gouged deeply with knife or hammer) to ?moderate? (scratched readily with knife or hammer) to ?hard? (scratched with difficulty with knife or hammer) to ?very hard? (can?t be scratched with knife or hammer). � Notes ? Any notes that the recorder thought were pertinent. � GlobalID ? Unique identifier assigned by software during geodatabase formation. � Rock_Descriptions OBJECTID ? Unique number assigned by software to identify each point observation. � Shape ? Type of feature, in all cases ?point.? � Rock Type ? Estimated during field evaluation. � Bedding Spacing, Orientation - Estimated and measured during field evaluation. � Fracture Spacing, Orientation - Estimated and measured during field evaluation. � Fracture Condition ? Estimated during field evaluation. � Hardness ? Estimated from hand specimens and ranging from ?soft? (moldable) to ?friable? (crumbles or powders) to ?low? (gouged deeply with knife or hammer) to ?moderate? (scratched readily with knife or hammer) to ?hard? (scratched with difficulty with knife or hammer) to ?very hard? (can?t be scratched with knife or hammer). � Strength ? Estimated from hand specimens and ranging from ?plastic? (easily molded) to ?friable? (crumbles with finger pressure) to ?weak? (crumbles under light hammer blows) to ?moderate? (withstands several firm hammer blows) to ?strong? (withstands heavy, ringing hammer blows) to ?very strong? (only dust produced by any hammer blow). � Decomposition/Mineral Alteration? Estimated during field evaluation. � Notes ? Any notes that the recorder thought were pertinent. � GlobalID ? Unique identifier assigned by software during geodatabase formation. � Source_Areas OBJECTID ? Unique number assigned by software to identify each point observation. � Shape ? Type of feature, in all cases ?point.? � Location ? Location on landslide where point was recorded, including ?flank,? ?headscarp,? ?toe,? and ?other.? � Failure Mode ? Failure mode of the landslide (Cruden and Varnes, 1996), including ?translational,? ?rotational,? and ?complex.? � Source Evacuation ? Relative amount of landslide volume that evacuated the source area during movement, including ?full? and ?partial.? � State of remaining slide mass, if any. ? Increasing disaggregation and reworking observed in landslide deposit from ?coherent? to ?disrupted? to ?fragmented? to ?remolded.? � Landslide Complex ? Whether the landslide was part of a complex (Cruden and Varnes, 1996; also noted therein as ?composite?) and, if so, state of the complex, including ?no,? ?yes, new,? ?yes, reactivated full,? and ?yes, reactivated partial.? � Base Located Within ? Material in which the landslide base was located. For landslide bases at material boundaries, both materials are listed. Observations include ?rock,? ?saprolite,? ?soil,? ?sap/rock,? ?soil/rock,? and ?soil/sap,? where ?sap? indicates saprolite. � Hillslope Curvature ? Overall curvature of the landslide location before the landslide occurred, including ?concave,? ?convex,? ?planar,? and ?other.? � Damage ? Human-made structures damaged by the landslide, if any, including ?house,? ?road,? ?none,? and ?other.? � Vegetation ? General description of vegetation in the landslide area. � Modified Slope ? Pre-landslide slope modifications that appeared to influence landslide occurrence. � Land Use ? General description of land use. � Mean Slope (degrees) ? A measured estimate of the overall pre-landslide source-area slope inclination. � Slope Length (m) ? A measured estimate of the along-slope length of the landslide source area. � Width (m) ? A measured estimate of the mean landslide source area width. � Mean Depth (m) - A measured estimate of the mean landslide source area depth. � Maximum Depth (m) - A measured estimate of the maximum landslide source area depth. � Notes ? Any notes that the recorder thought were pertinent. � Acknowledgements: � This work was supported in part by the Additional Supplemental Appropriations for Disaster Relief Requirements Act, 2018 (P.L. 115-123). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. References: Bessette-Kirton, E.K., Cerovski-Darriau, C., Schulz, W.H., Coe, J.A., Kean, J.W., Godt, J.W, Thomas, M.A., and Hughes, K. Stephen, 2019a, Landslides Triggered by Hurricane Maria: Assessment of an Extreme Event in Puerto Rico: GSA Today, v. 29, doi:10.1130/GSATG383A.1 � Bessette-Kirton, E.K., Coe, J.A., Kelly, M.A., Cerovski-Darriau, C. and Schulz, W.H., 2019b, Map data from landslides triggered by Hurricane Maria in four study areas of Puerto Rico: U.S. Geological Survey data release, https://doi.org/10.5066/P9OW4SLX. � Cruden, D.M., and Varnes, D.J., 1996, Landslide types and processes. In: Turner, A.K., Schuster, R.L. (Eds.), Landslides, Investigation and Mitigation, Transportation Research Board Special Report 247: National Research Council, Washington, D.C., p. 36?75. � Hughes, K.S., Bayouth Garc�a, D., Mart�nez Milian, G.O., Schulz, W.H., and Baum, R.L., 2019, Map of slope-failure locations in Puerto Rico after Hurricane Mar�a: U.S. Geological Survey data release, https://doi.org/10.5066/P9BVMD74. � Larsen, M.C., and Parks, J.E., 1997, How wide is a road? The association of roads and mass-wasting in a forested montane environment: Earth Surface Processes and Landforms, v. 22, p. 835-848. Quantum Spatial, Inc., 2017, FEMA PR Imagery: https://s3.amazonaws.com/fema-cap-imagery/Others/Maria (accessed October 2017). �

2017年9月，飓风玛丽亚（Hurricane Maria）在波多黎各全境山区引发大范围滑坡，后续通过航空影像共识别出超过7.1万处滑坡（Hughes等，2019）。多数滑坡以碎屑流形式启动，且多发生于覆盖于腐岩（saprolite）和基岩之上的松散土体，以及覆盖于弱风化岩石之上的腐岩中（如Bessette-Kirton等，2019a）。为深入解析飓风玛丽亚引发的滑坡、碎屑流及其发育介质的特征，本研究对118处滑坡、46处（多位于滑坡壁内的）土体露头、24处腐岩露头及37处岩石露头开展了踏勘级调查，本数据集即包含本次调查的相关成果。

本次研究选取的滑坡大多来自2017年10月9日至15日采集的航空影像（Quantum Spatial, Inc., 2017），重点关注了4处滑坡数量密集的研究区——该区域此前已通过航空影像与激光雷达（LiDAR）数据完成过相关研究（Bessette-Kirton等，2019b）。此外，研究团队还选取了分布于波多黎各主岛山区各处、发育于玛丽亚飓风引发滑坡高发地质构造中的滑坡进行野外调查。最终选取的滑坡均相对易于从道路抵达，但研究团队尽量选择未明显受道路施工或排水工程影响的滑坡。不过此前一项研究显示，波多黎各的滑坡在道路附近发生的概率是远离道路区域的约5倍（Larsen和Parks，1997）。野外调查于2018年6月至2022年3月间断续开展。

本次发布的数据采用ESRI ArcGIS构建的文件地理数据库（file geodatabase）格式，包含4个点要素类：土体描述（Soil_Descriptions）、腐岩描述（Saprolite_Descriptions）、岩石描述（Rock_Descriptions）以及滑坡源区（Source_Areas），其中滑坡源区要素类用于记录滑坡启动位置。

滑坡位置与几何尺寸的野外测量采用卷尺、激光测距仪、手持水准仪、测斜仪、袖珍经纬仪、地质罗盘，以及搭载GPS技术与蜂窝天线距离测算功能的移动设备（智能手机、平板电脑）完成。部分介质的野外无侧限抗压强度（unconfined compressive strength）与不排水抗剪强度（undrained shear strength）分别通过手动贯入仪与手动十字板剪切仪估算，相关结果分别记录于“稠度/密实度（Consistency/Compactness，对应无侧限抗压强度）”与“备注（Notes，对应不排水抗剪强度）”字段中。土体与腐岩的颜色通过孟塞尔色卡（Munsell color charts）目视估算。野外数据通过搭载ESRI ArcGIS Collector软件的移动设备采集，后续通过ArcGIS桌面软件进行整合。研究团队对多数（而非全部）调查对象拍摄了照片，相关照片同样存储于该地理数据库中。下文将分别介绍4个点要素类的属性字段，附加信息可查阅随附的元数据文件。

### 土体描述（Soil_Descriptions）
- 对象编号（OBJECTID）：由软件为每个点观测要素分配的唯一识别编号。
- 形状（Shape）：要素类型，所有记录均为"point"（点）。
- 土体类型（Soil Type）：通过目视与人工估算得到的主要土体类型，辅以少量占比的次要土体类型修正。土体类型主要包括黏土（clay）、粉土（silt）、砂土（sand）与砾石（gravel）：黏土指粒径≤0.002 mm的颗粒，粉土指粒径为0.002 mm~0.075 mm的颗粒，砂土指粒径为0.075 mm~4.75 mm的颗粒，砾石指粒径为4.75 mm~75 mm的颗粒。当次要类型占比超过30%时，可通过次要类型修饰主要类型（如"粉质黏土"）。非主要土体类型的占比可通过以下术语描述：占比1%~10%为"微量（trace）"，10%~20%为"少量（little）"，20%~35%为"部分（some）"，35%~50%为"and"（原文如此）。
- 孟塞尔色值（Munsell Color）：在野外含水率条件下，通过手标本目视结合孟塞尔色卡估算得到的颜色。
- 野外含水率（Field Moisture）：按湿润程度递增分为四级：干燥（dry，粉末状，加热后不变色）、湿润（moist，可搓成直径1/8英寸的丝条，加热后变色）、潮湿（wet，柔软发黏，可维持塑形形状）、饱和（saturated，可自由渗出水分）。
- 塑性（Plasticity）：基于野外含水率或更高含水率的标本估算得到，按可搓成1/8英寸直径丝条的难易程度分为：非塑性（non-plastic）、弱塑性（slightly plastic）、中塑性（moderately plastic）、塑性（plastic）与高塑性（highly plastic），塑性程度随"高塑性"方向递增，随"非塑性"方向递减。
- 野外干强度（Field Dry Strength）：通常基于野外含水率或更低含水率的标本估算，按强度从低到高分为：无/极弱（none/very little，受扰动即碎裂）、弱（slight，易折断）、中等（medium，需稍用力方可折断）、高（high，需较大用力方可折断，但无法压成粉末）、极高（very high，用手指压力无法折断或压碎）。
- 胶结程度（Cementation）：通常基于粉土、砂土与砾石类野外标本估算，分为：无胶结（none）、弱胶结（weak，手指按压即可碎裂）、中胶结（moderate，手指无法折断，但可用锤子击碎）、强胶结（strong，需用锤子施力方可击碎）。
- 结构（Structure）：对观测到的各类结构的描述，如裂隙、层理、擦痕（slickensides）、团粒等。
- 稠度/密实度（Consistency/Compactness）：基于野外含水率的标本估算得到，部分结果通过手动贯入仪以kg/cm²为单位量化。针对黏土，稠度从低到高依次为：极软（very soft，握拳时可从指缝挤出，0~0.25 kg/cm²）、软（soft，可轻松用手指塑形，0.25~0.5 kg/cm²）、中硬（medium stiff，需较强手指压力方可塑形，0.5~1.0 kg/cm²）、硬（stiff，较强手指压力可留下压痕，1.0~2.0 kg/cm²）、极硬（very stiff，较强手指压力仅留下轻微压痕，2.0~4.0 kg/cm²）、坚硬（hard，铅笔尖仅能留下轻微压痕，>4.0 kg/cm²）。针对粉土与砂土，密实度从低到高依次为：极松散（very loose，握拳时可从指缝挤出，0~0.25 kg/cm²）、松散（loose，可通过手指塑形，0.25~0.75 kg/cm²）、中密（medium dense，较强手指压力可留下压痕，0.75~2.0 kg/cm²）、密实（dense，较强手指压力仅留下轻微压痕，2.0~4.0 kg/cm²）、极密实（very dense，铅笔尖仅能留下轻微压痕，>4.0 kg/cm²）。
- 颗粒描述（Particle Description）：对颗粒粒径分布及颗粒本身的一般性描述。
- 备注（Notes）：记录人员认为相关的补充说明。
- 全局唯一标识符（GlobalID）：地理数据库构建过程中由软件分配的唯一识别编号。

### 腐岩描述（Saprolite_Descriptions）
- 对象编号（OBJECTID）：由软件为每个点观测要素分配的唯一识别编号。
- 形状（Shape）：要素类型，所有记录均为"point"（点）。
- 土体类型（Soil Type）：同土体描述要素类的土体类型定义。
- 孟塞尔色值（Munsell Color）：同土体描述要素类的定义。
- 野外含水率（Field Moisture）：同土体描述要素类的定义。
- 塑性（Plasticity）：同土体描述要素类的定义。
- 野外干强度（Field Dry Strength）：基于手标本估算，按强度从低到高分为：塑性（plastic，易塑形）、松散易碎（friable，受手指压力即碎裂）、弱（weak，受轻锤敲击即碎裂）、中等（moderate，可承受数次用力锤击）、强（strong，可承受重型锤击）、极强（very strong，锤击仅产生粉尘）。
- 胶结程度（Cementation）：同土体描述要素类的定义。
- 结构（Structure）：同土体描述要素类的定义。
- 稠度/密实度（Consistency/Compactness）：同土体描述要素类的定义。
- 颗粒描述（Particle Description）：同土体描述要素类的定义。
- 母岩类型（Parent Rock Type）：野外调查期间估算得到的母岩类型。
- 层理间距与产状（Bedding Spacing, Orientation）：野外调查期间估算并测量得到的层理间距与产状。
- 裂隙间距与产状（Fracture Spacing, Orientation）：野外调查期间估算并测量得到的裂隙间距与产状。
- 裂隙状态（Fracture Condition）：野外调查期间估算得到的裂隙状态。
- 硬度（Hardness）：基于手标本估算，从低到高分为：软（soft，可塑形）、松散易碎（friable，碎裂或粉化）、低（low，用刀或锤可刻出深痕）、中等（moderate，用刀或锤易划出痕迹）、硬（hard，用刀或锤划出痕迹较困难）、极硬（very hard，用刀或锤无法划出痕迹）。
- 备注（Notes）：同土体描述要素类的定义。
- 全局唯一标识符（GlobalID）：同土体描述要素类的定义。

### 岩石描述（Rock_Descriptions）
- 对象编号（OBJECTID）：由软件为每个点观测要素分配的唯一识别编号。
- 形状（Shape）：要素类型，所有记录均为"point"（点）。
- 岩石类型（Rock Type）：野外调查期间估算得到的岩石类型。
- 层理间距与产状（Bedding Spacing, Orientation）：同腐岩描述要素类的定义。
- 裂隙间距与产状（Fracture Spacing, Orientation）：同腐岩描述要素类的定义。
- 裂隙状态（Fracture Condition）：同腐岩描述要素类的定义。
- 硬度（Hardness）：同腐岩描述要素类的定义。
- 强度（Strength）：基于手标本估算，从低到高分为：塑性（plastic，易塑形）、松散易碎（friable，受手指压力即碎裂）、弱（weak，受轻锤敲击即碎裂）、中等（moderate，可承受数次用力锤击）、强（strong，可承受重型锤击）、极强（very strong，锤击仅产生粉尘）。
- 风化/矿物蚀变程度（Decomposition/Mineral Alteration）：野外调查期间估算得到的风化与矿物蚀变程度。
- 备注（Notes）：同土体描述要素类的定义。
- 全局唯一标识符（GlobalID）：同土体描述要素类的定义。

### 滑坡源区（Source_Areas）
- 对象编号（OBJECTID）：由软件为每个点观测要素分配的唯一识别编号。
- 形状（Shape）：要素类型，所有记录均为"point"（点）。
- 位置（Location）：测点在滑坡上的位置，包括"坡肩（flank）"、"后壁（headscarp）"、"坡脚（toe）"与"其他（other）"。
- 破坏模式（Failure Mode）：滑坡的破坏模式（Cruden与Varnes，1996），包括"平移式（translational）"、"旋转式（rotational）"与"复合式（complex）"。
- 源区运移量（Source Evacuation）：滑坡运动过程中从源区运移的相对体积，包括"完全运移（full）"与"部分运移（partial）"。
- 剩余滑体状态（若有）：滑坡堆积体的解离与再改造程度从低到高分为：完整（coherent）、破碎（disrupted）、碎裂（fragmented）、重塑（remolded）。
- 滑坡复合体（Landslide Complex）：该滑坡是否属于复合滑坡（Cruden与Varnes，1996，亦称为"复合式"），若为是，则复合体状态分为：否（no）、是，新滑坡（yes, new）、是，完全复活（yes, reactivated full）、是，部分复活（yes, reactivated partial）。
- 滑带基底所在介质（Base Located Within）：滑坡滑带所处的介质。若滑带位于两种介质的边界，则同时列出两种介质，可选值包括：岩石（rock）、腐岩（saprolite）、土体（soil）、腐岩/岩石（sap/rock）、土体/岩石（soil/rock）、土体/腐岩（soil/sap），其中"sap"代表腐岩。
- 坡向曲率（Hillslope Curvature）：滑坡发生前测点所在坡地的整体曲率，包括"凹形（concave）"、"凸形（convex）"、"平面（planar）"与"其他（other）"。
- 破坏损伤（Damage）：滑坡造成的人工构筑物损伤情况，包括"房屋（house）"、"道路（road）"、"无损伤（none）"与"其他（other）"。
- 植被（Vegetation）：滑坡区域植被的一般性描述。
- 边坡改造情况（Modified Slope）：滑坡发生前对边坡进行的、可能影响滑坡发生的改造措施。
- 土地利用（Land Use）：滑坡区域的土地利用类型描述。
- 平均坡度（°）（Mean Slope (degrees)）：滑坡发生前源区的平均坡面倾角估算值。
- 坡长（m）（Slope Length (m)）：滑坡源区沿坡面方向的长度估算值。
- 平均宽度（m）（Width (m)）：滑坡源区的平均宽度估算值。
- 平均深度（m）（Mean Depth (m)）：滑坡源区的平均深度估算值。
- 最大深度（m）（Maximum Depth (m)）：滑坡源区的最大深度估算值。
- 备注（Notes）：同土体描述要素类的定义。

### 致谢
本研究部分得到《2018年救灾补充拨款法案》（Public Law 115-123）的资助。文中提及的商业名称、公司或产品仅用于描述目的，并不代表美国政府的认可。

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