The reactivation of ancient landslides in the Emilia-Romagna Region (Italy): risk-reduction strategies
In Emilia-Romagna, over 70.000 landslide bodies cover one fifth of the hilly and mountainous territory. The majority of them originated as earth-flows after the last glacial maximum and grew during the rainiest periods of the Holocene through the superimposition of new earth flows.
These ancient landslide bodies still represent a threat. In fact, in the Emilia-Romagna Apennines as well as in the entire Northern Apennines, almost all the present-day landslide activity is due to the reactivation of them. Consequently, territorial planning and geo-thematic cartography are fundamental tools for the reduction of risk. Emilia-Romagna geo-thematic cartography (1:10.000) is legally binding and regulates land use in regional, municipal and basin plans.
The Emilia-Romagna Apennines are the portion of the Northern Apennines under the administration of the Emilia- Romagna Region (approximately 12.000 km²), corresponding to the northern flank of the chain.
In the Emilia-Romagna Apennines the Geological, soil and seismic risk Area has identified over 70.000 landslide bodies, covering one fifth of the 12,000 sq. km. territory. From the morphological point of view, a good 90% of them are large, ancient earth flows.
Ancient dormant earth flows have been areas wrongly judged as suitable for human settlement since ancient times, thanks to the low slope of their frontal and mid-accumulation zones, a real trap for many hamlets and villages. As a result, 281 inhabited centres (defined as four or more buildings, excluding “scattered houses”) lie upon or are directly affected by active landslides and 1608 by dormant landslides. Dozens of municipal centres are among them.