Dataset Direct Download Service (WFS): N_ZONE_ALEA_PPRN_20140249_S_032

The mapping of the hay removal of clays in the commune of Isle-de-Noé in the Gers department is extracted from the departmental mapping from the BRGM. This mapping is a zoning of the probability of occurrence of the phenomenon of shrink-inflating of clay soils. A susceptibility map was first drawn up on the basis of purely physical criteria by the BRGM from the geological maps of the department, which were interpreted taking into account the following factors for each geological formation: — the proportion of clay material within the formation (lithic analysis); — the proportion of blowing minerals in the clay phase (mineralogical composition); — the geotechnical behavior of the material. For each of the clay formations identified, the hazard level is ultimately the result of the level of susceptibility thus obtained with the density of sinister swelling, reported to 100 km² of actual urbanised outcropping surface.本数据集所采用的热尔省（Gers）伊勒德诺埃（Isle-de-Noé）公社范围内黏土收缩-膨胀现象（hay removal of clays）区划图，源自法国地质矿产调查局（Bureau de Recherches Géologiques et Minières，BRGM）编制的省级区划图。该区划图为黏土土壤收缩-膨胀现象发生概率的分区图。法国地质矿产调查局（BRGM）首先以该省地质图为基础，基于纯物理准则编制了敏感性分区图，编制过程中针对各地质单元考量了以下因素： — 地层内黏土物质占比（岩相分析）； — 黏土相中风成矿物占比（矿物组成）； — 该物质的岩土工程特性。 针对所识别的各黏土地层，最终的灾害等级由上述敏感性等级结合灾害性胀缩密度确定，该密度以每100平方公里实际出露的城市化地表面积为基准进行统计。