D. Castaldini

AN INTEGRATED APPROACH FOR ANALYSING EARTHQUAKE-INDUCED SURFACE EFFECTS: A CASE STUDY FROM THE NORTHERN APENNINES, ITALY

Abstract This paper illustrates research addressing the subject of the earthquake-induced surface effects by means of a multidisciplinary approach: tectonics, neotectonics, seismology, geology, hydrogeology, geomorphology, soil/rock mechanics have been considered. The research is aimed to verify in areas affected by earthquake-triggered landslides a methodology for the identification of potentially unstable areas. The research was organized according to regional and local scale studies. In order to better emphasise the complexity of the relationships between all the parameters affecting the stability conditions of rock slopes in static and dynamic conditions a new integrated approach, Rock Engineering Systems (RES), was applied in the Northern Apennines. In the paper, the different phases of the research are described in detail and an example of the application of RES method in a sample area is reported. A significant aspect of the study can be seen in its attempt to overcome the exclusively qualitative aspects of research into the relationship between earthquakes and induced surface effects, and to advance the idea of beginning a process by which this interaction can be quantified.

Geomorphological identification, classification and spatial distribution of coastal landforms of Malta (Mediterranean Sea)

This paper presents the outcomes of a geomorphological investigation carried out along the coasts of the island of Malta and provides a detailed classification of the Maltese coastline based on the identification and definition of specific coastal geomorphotypes. The results of field surveys, supported by air-photo interpretation, have led to the production of a coastal geomorphological map at 1:30,000 scale which outlines the processes and related deposits and landforms. The latter are the result of the complex interplay of structural, gravitational, coastal and karst processes. Moreover, radiocarbon dates of marine organisms encrusted on boulders mapped along the NE coast are presented.

Appraisal of active deformation from drainage network and faults: inferences from non-linear analysis

This investigation reveals the relative susceptibility of the landscape to surface deformation by means of non-linear analysis of drainage network. The geometrical characteristics of the drainage network are quite capable of discriminating the impact of active tectonics. This study uses fractal dimension, lacunarity and succolarity techniques to demarcate numerous zones where the drainage network is tectonically controlled. Rose diagrams are used to compare drainage network orientation with the faults. This investigation is primarily based on the basic concept that the drainage network is subject to linearized and modify from its natural geometrical shape and orientation under the influence of tectonic activity. The areas with similar fractal dimension can be further discriminated by lacunarity and succolarity analysis. A detailed textural investigation of the drainage network (Strahler order ≥2) of Secchia, Panaro and Reno mountain river basins in northern Apennines, Italy is carried out to analyze the linearization, translational invariance and rotation of the stream patterns. The low fractal dimension values of Secchia, Panaro, Reno, Dragone, Dolo and Setta rivers indicate tectonically controlled drainage. The results reveal that the fractal dimension, lineament density and orientation analysis of drainage network and faults is a significant tool to pinpoint areas susceptible to active deformation.

Rumours Related to the 2012 Emilia Seismic Sequence

In the aftermath of an earthquake, pseudo-scientific, scaremongering rumours spread very quickly and with greater effect than correct scientific information. The aim of this article is to describe the authors’ observations and examine how rumours linked to seismic shocks spread in the community following the strong 2012 seismic sequence in Emilia (northern Italy). During the two mainshocks, 27 people lost their lives, over 400 persons were injured and 14,000 families were evacuated. In the weeks following the mainshocks, in collaboration with other universities and research groups, we carried out field surveys, organized interviews and public meetings with the local population and held direct contacts with journalists and reporters. The mainshocks of this sequence (ML = 5.9 on 20th May and ML = 5.8 on 29th May) found the local population culturally and psychologically unprepared. As a consequence, there were attitudes of suspicion and lack of trust towards the authorities and the scientific community. Many people considered these earthquakes induced by human activities such as exploitation of subsurface resources or fracking. Moreover, in spite of the experts explaining in all possible ways the origin of earthquakes and emphasizing their unpredictability, the population has given credit to various groundless alarms on the basis of gas emissions, bubbling water and ground fractures. In order to effectively counter the spreading of wrong convictions about earthquakes, a constant, updated dialogue must be kept up between the population and the scientific community.

Mud Volcanoes in the Emilia-Romagna Apennines: Small Landforms of Outstanding Scenic and Scientific Value

Mud volcanoes are emissions of cold mud due to the ascent to the surface of salty and muddy waters mixed with gaseous (methane) and, in minor part, fluid hydrocarbons (petroleum veils) along faults and fractures. In the Emilia-Romagna Apennines (Northern Italy) mud volcanoes are closely linked to the active tectonic compression associated with a thrust of regional importance. They are mostly cone shaped and show variable geometry and size, ranging from one to few metres, and are located in 19 sites in the northwestern part of the Apennines. The mud volcanoes of the region have been known since a long time and have always aroused great interest due to their outstanding scenic value. In the past, the mud volcano emissions have been used in many ways: the mud was applied for cosmetic use and the natural oil was much appreciated for its balsamic and purgative properties. In the last decades, the mud volcanoes have represented relevant tourist attractiveness.

DEM-based drainage network analysis using steepness and Hack SL indices to identify areas of differential uplift in Emilia–Romagna Apennines, northern Italy

The landscape evolution in active orogens is mainly dictated by the interaction of tectonic and erosional processes. Semi-automated river profile analysis has been performed to investigate the influence of neotectonics on topographic evolution in Emilia–Romagna Apennines, northern Italy. The objective is to use the drainage network from digital elevation model (DEM) to constrain the active structures and prepare the relative uplift rates, steepness and Hack index maps of the region for the first time. Profiles of Secchia, Panaro and Reno rivers and their tributaries were modelled using stream length gradient index and area-slope analysis for concavity, steepness and uplift indices. These proved to be the most useful topographic metrics for recording the effects of local-scale and/or regional-scale active faults. Different zones are distinguished through differential relative uplift. The differences in uplift rates have been found both transverse and parallel to the mountain chain. The highly deformed areas correspond to the presence of active faults. Description of drainage pattern, river profiles, knickpoints, steepness and stream gradient analysis (Hack SL index) are found to be in good agreement with other datasets, signifying that local tectonic deformation of the study area is embedded within a broader, regional uplift of the mountain chain, in association with compressional and extensional structures.