Abstract. On 6 April 2009 at 01:32:39 UT a strong earthquake occurred west of L'Aquila at the very shallow depth of 9 km. The main shock local magnitude was M l = 5.8 (Mw = 6.3). Several powerful aftershocks occurred the following days. The epicentre of the main shock occurred 6 km away from the Geomagnetic Observatory of L'Aquila, on a fault 15 km long having a NW-SE strike, about 140 • , and a SW dip of about 42 • . For this reason, L'Aquila seismic events offered very favourable conditions to detect possible electromagnetic emissions related to the earthquake. The data used in this work come from the permanent geomagnetic Observatories of L'Aquila and Duronia. Here the results concerning the analysis of the residual magnetic field estimated by means of the inter-station impulse response functions in the frequency band from 0.3 Hz to 3 Hz are shown.

We investigated whether the joint inversion of geodetic and stress direction data can constrain long‐term fault slip rates in the central Apennines, and ultimately how extension is partitioned among fault slip and bulk lithosphere permanent strain. Geodetic velocities are collected in the fault interseismic stage with steady secular deformation; thus, long‐term estimates can be derived with a model of elastically unloading seismogenic faults within a viscously deforming lithosphere. As the average spacing of permanent Global Navigation Satellite Systems (GNSS) stations is similar to the average length of seismogenic faults (25–35 km), if not larger, we decided to merge permanent and temporary GNSS measurements, resulting in a denser geodetic data set. Given that most normal faults in the Apennines have slip rates around or below 1 mm/a, and most campaign GNSS velocities carry similar uncertainties, simple local back slip models cannot be applied. More sophisticated modeling is required to extract reasonable bulk deformation rates and long‐term fault slip rates at signal‐to‐noise ratio of order unity. Given the spatial distribution of the GNSS network, we estimated the long‐term slip rate of seven major fault systems that are in satisfactory agreement with available geological slip rates. The resulting spatial distribution of bulk deformation rates locally fits short‐term transients; in other cases, they represent the currently unclear signature of tectonic processes like upper‐crustal viscoplastic deformation and aseismic slip, or indicate missing faults in the adopted database. We conclude that the time is ripe for determining fault slip rates using geodetic and stress direction data, particularly where fault activity rates are hard to determine geologically.

The 2016 central Apennines earthquake sequence was caused by slip on an extensional fault system and resulted in sizable coseismic surface deformation. The most evident effects occurred along the western slope of Mount Vettore, a geologically and morphologically complex mountain ridge. Steep topography and rheological contrasts are known to have strongly controlled the coseismic deformation pattern during a number of different earthquakes that occurred in mountainous areas worldwide. Nevertheless, so far the role of seismically induced slope failures has not been taken into account in the interpretation of the surface fractures caused by the 2016 earthquake sequence. We modeled the static and dynamic slope stability along the western flank of Mount Vettore and in the underlying Piano Grande plain. Combining the slope stability analysis with geomorphic and geological analyses, we show that the coseismic fractures are distributed along the most unstable areas of the western flank of Mount Vettore and can be partly explained by shaking‐induced mechanisms such as gravity‐driven displacement, compaction, and secondary ground failure. Conversely, in the Piano Grande plain the fracture pattern is not affected by topography or rheology contrasts, suggesting that it is positively caused by tectonic faulting. Different processes, such as gravitational and erosional‐depositional phenomena, may contribute to the exposure of fault scarps during both the coseismic and interseismic periods. Attributing the surface deformation entirely to tectonic faulting, especially in complex mountainous terrains such as the Apennines, may lead to an incorrect assessment of fault displacement and fault slip rate and hence of seismic hazard.

Abstract. The technological and the scientific objectives of the MEM (Magnetic and Electric fields Monitoring) project concerning to the study of the electromagnetic signals linked with the Earth's crustal activity are reported. The MEM project has been activated in Central Italy to create a network of observatories so as to monitoring the electromagnetic signals, both natural and artificial, in the frequency band [0.001 Hz-100 kHz]. Some examples of the developed instrumentation and the know-how transfer to the industry are reported. We also report some results obtained in the first MEM station installed in the area of the INGV (Italian Istituto Nazionale di Geofisica e Vulcanologia) Observatory of L'Aquila. Using the single station magnetotelluric approach we have obtained some valuables information about the underground resistivity structure in the area of the measurement station. Concerning to the study of the magnetic signals linked with the tectonic activity we have reported an example of the long term behaviour of the magnetic induction vectors characteristics in the lower frequency band [0.001-0.5] Hz, showing their normal behaviour when no large crustal changes due to geodynamical processes are present.

Abstract. We are reporting the technological and scientific objectives of the MEM project. The MEM project has been activated in the INGV Observatory of L'Aquila to create in Central Italy a network of observatories in order to monitoring the electromagnetic signals in the frequency band [0.001 Hz-100 kHz]. Some examples of the instrumentation developed in the frame of the project are reported. An innovative technique, based on the wide band interferometry is proposed to obtain detailed information concerning the several detected electromagnetic sources. Moreover, data from each station will be elaborated to investigate different sectors as the structure of ground electric conductibility, the electromagnetic phenomena connected with seismic activity, the separation of the electromagnetic fields originated in the Earth's interior and the electromagnetic phenomena originated in the magnetosphere, in the ionosphere and in the Earth-ionosphere cavity.