Press archives as temporal records of landslides in the North of Spain: relationships between rainfall and instability slope events

This paper evaluates the usefulness of press archives as temporal records of landslides in Asturias, northern Spain. It also shows the potential for this kind of information in the establishment of relationships between slope instability events and climatic parameters. In this way, a search has been made of Asturian regional newspaper archives, including data from the period between January 1980 and June 1995 (5290 newspapers reviewed). The methodology developed shows some limitations, due to the low frequency of news items relating to landslides and the lack of scientific data collected by correspondents. Moreover, there is a bias towards instability events concerning people, infrastructures and other human resources. Statistical analysis of 209 news items relating to slope instability is useful to establish the geological and spatial location of landslides. Fifty-one point two percent of them are situated in the Central Coal Basin, with a sedimentary siliceous bedrock. Temporal data are accurate in 83.2% of the cases. A comparison between climatic and slope instability events reveals that 79% of the landslides developed during rainfall events, associated with the monthly 24-h rainfall maximum values. Highest landslide frequencies are reached in years with more than 1000 mm rainfall, mainly in December and April.