N_ZONE_ALEA_PPRN_20140192_S_032

The mapping of the hay removal of clays in the commune of Blousson-Sérian 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.本数据集取自法国地质矿业研究局（BRGM）编制的热尔省全域地质图件，内容为热尔省布卢松-塞里扬（Blousson-Sérian）市镇范围内的黏土胀缩相关图件。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，基于纯物理标准编制了敏感性分区图，编图过程中针对各地质单元，综合考量了以下影响因素：— 地质单元内黏土物质占比（岩性分析）；— 黏土相内膨胀矿物占比（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质单元，最终的灾害等级由前述敏感性等级结合有害胀缩事件密度确定，统计基准为每100平方千米实际出露的城市化地表。