Map visualisation service (WMS) of the dataset: N_ZONE_ALEA_PPRN_20140381_S_032

The mapping of the hazard removal swelling of the clays in the municipality of Ramouzens in the department of Gers is extracted from the departmental cartography resulting from the BRGM. This mapping is a zoning of the probability of occurrence of the phenomenon of withdrawal-swelling of clay fields. A susceptibility map was first drawn up on the basis of purely physical criteria by 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 (Lithological analysis); — the proportion of inflating minerals in the clay phase (mineralogical composition); — the geotechnical behaviour 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 shrinkage swelling, reported to 100 km² of outcropping area actually urbanised.热尔省（Gers）拉姆赞斯市镇（Ramouzens）内黏土胀缩灾害的区划图，源自法国地质与矿业研究局（BRGM）编制的省级制图成果。该区划图针对黏土地层胀缩现象的发生概率进行分区划定。法国地质与矿业研究局（BRGM）首先依托该省地质图，基于纯物理准则编制了易发性区划图，编制过程中针对每一处地质单元，综合考量了以下因素： — 地层内黏土物质占比（岩性分析）； — 黏土组分中膨胀矿物占比（矿物组成分析）； — 该物质的岩土工程特性。 针对已识别的每一处黏土地层，最终的灾害等级由上述易发性等级结合以每100平方公里已实际城市化的出露区域为基准归一化的缩胀密度共同确定。