Simple download service (Atom) of the dataset: N_ZONE_ALEA_PPRN_20140421_S_032

The mapping of the hay removal of clays in the commune of Lannemaignan 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.本数据集提取自法国地质矿产调查局（BRGM）编制的热尔省全域地质绘图，内容为热尔省朗讷曼昂（Lannemaignan）市镇范围内的黏土胀缩现象相关绘图。该绘图为黏土土壤胀缩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易发性图，编制过程中针对各地质单元，综合考量了以下因素： — 地层内黏土物质的占比（岩相分析）； — 黏土相中膨胀矿物的占比（矿物组成分析）； — 岩土体的工程地质性状。 针对已识别的各黏土地层，最终的灾害等级由上述易发性等级结合灾害性胀缩密度（按每100平方公里实际出露的城市化地表面积折算）共同确定。