Filipe Telmo Jeremias

The Carrascal Caves are located approximately 10 kilometres west of Lisbon, Portugal. They result from the artificial excavation of a nodular limestone layer with a high clay content, deposited between layers of compact limestone dating from the Cretaceous period. This material was used for several purposes, including the reconstruction of Lisbon’s downtown following the 1755 earthquake. From the 1970s onwards, the land above the caves has been progressively occupied by illegal constructions, and the area is currently undergoing urban redevelopment. Following a collapse in April 2022 that affected a house and part of a road under construction, the stability conditions of the area were analysed. The study was based on surface geological mapping, which included both the characterisation of geological features and the identification of the main instability issues. The results indicate that the study area is prone to vertical ground movements, which can lead to the collapse of large blocks inside the cave galleries. These instability problems outline an extremely hazard scenario for resident population and local traffic. The factors controlling block dimensions are stratification and two sets of orthogonal sub‑vertical joints, which are highly continuous and extremely wide. Recommendations are issued for priority actions to reduce the identified risks.

Mudrocks are fine-grained clay-rich rocks that comprise different lithotypes forming more than 60% of all sedimentary rocks, and thus, they occur frequently in engineering projects either as natural ground or as made ground. These rocks may display a range of engineering behaviours controlled mostly by their composition and structural features. Due to rapid breakdown and susceptibility to volume changes, they may cause problems both during and after construction. Research into the susceptibility of mudrocks to breakdown aims to predict problematic behaviour and provide guidance for avoiding or mitigating these effects. Low-durability materials that disintegrate during sampling and testing can be especially difficult to assess. The paper reviews laboratory techniques for mudrock characterization as well as describes geological and engineering geological classification schemes generally used to describe and classify these materials. The value of some of the tests and determinations in the evaluation of a series of mudrock data taken from the literature is presented.

The Platform for Atlantic Geohazard Risk Management (AGEO) is a new project co-financed under the Interreg Programme for the Atlantic Area which aims to launch five Citizens’ Observatory pilots on geohazards according to regional priorities:Citizens’ observatory on rockfalls and rockfall-triggers in the Canary Islands, Spain Peat-slides and peat massmovement monitoring and control in Cuilcagh Mountain, Northern Ireland Multihazard Citizens’ Observatory in Lisbon, Portugal Citizens’ observatory of slope instability monitoring along the Cliffs of Moher, Ireland Citizens’ observatory of vulnerability to coastal Risks in Brittany, france These will demonstrate how citizens’ involvement in geohazard risks prevention can strengthen regional and national risk management systems. Instituto Superior Técnico (Portugal) leads the consortium of AGEO that also counts with several other partners from Portugal, Spain, France, Ireland and the United Kingdom.AGEO will engage with local communities to actively participate in risk preparedness and monitoring and incorporate local capacities into risk management systems. Experiences gained during the implementation of the Citizens’ Observatory pilots will be used to formulate recommendations for the creation of future observatories in response to the widest range of hazards (both natural and human-induced) faced in the Atlantic region.The Observatories are part of the phenomenon of citizen science.  As defined by the EC, “Citizens' Observatories are community-based environmental monitoring and information systems. They build on innovative and novel Earth observation applications embedded in portable or mobile personal devices.  This means that citizens can help and be engaged in observing our environment.”There are many other definitions, as it is still a novel concept, but for this project the one above will be used. It is an observatory in a sense that we need careful monitoring of the risks that will be defined per region in line with a set of parameters to be defined through engaging with participating citizens to be filled in by the participating citizens. This approach lends the opportunity of collecting large amounts of data for very little to no money with the added bonus of the territorial coverage such approach can grant. Additionally, spatial data infrastructures and services already in place, e.g. Copernicus, will support the assessment and monitoring of geohazards and risk management systems.AGEO is also organizing workshops in each participating region to ensure the citizens understand the role they play in preventing and mitigating natural risks by being part of the observatories and hopefully encouraging new members to join. These workshops will be held in the national language of the region and are to be tailored to the different audiences and will democratize the use of the observatories by listening to the people using them and taking into account their needs.