Dataset Direct Download Service (WFS): N_ZONE_ALEA_PPRN_20140367_S_032

The mapping of the hay removal of clays in the commune of Dému in the department of Gers is extracted from the departmental mapping derived 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业研究局（BRGM）编制的省级图件，为热尔省（Gers）代米市镇（Dému）内黏土胀缩现象的制图成果。该图件为黏土土壤胀缩现象发生概率的分区图。法国地质矿业研究局（BRGM）首先依托该省地质图件，基于纯物理标准绘制了胀缩易感性图，制图过程中针对每一类地质地层，综合考量了以下因素： — 地层内黏土物质的占比（岩性分析）； — 黏土相中吹蚀矿物的占比（矿物组成分析）； — 该物质的岩土工程性状。 针对已识别的每一类黏土地层，最终的灾害等级由上述方法得到的易感性等级，结合以每100平方千米实际出露的城市化地表为基准的灾害性胀缩事件密度共同确定。