Simple download service (Atom) of the dataset: N_ZONE_ALEA_PPRN_20140210_S_032

The mapping of the hay removal of clays in the commune of Crastes 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.本次提取自法国地质矿产调查局（BRGM）省级制图成果的图件，针对热尔省（Gers）克雷斯特公社（Crastes）内的黏土开展编制，具体为该区域黏土收缩-膨胀（shrink-inflating）现象发生概率的分区图。该敏感性分区图最初由BRGM依托该省地质图件，基于纯物理准则编制完成；编制过程中针对每个地质单元，综合考量了以下因素： — 地层内黏土物质占比（岩相分析）； — 黏土相中膨胀性矿物占比（矿物组成分析）； — 该物质的岩土工程特性。 针对每一个已识别的黏土地层，最终的灾害等级由前述得到的敏感性等级结合灾害性胀缩密度得出，该密度以每100平方千米实际出露的城市化地表面积为统计基准。