The fault system monitored is that of the Upper Tiber Valley
In PHOTO 1 one of the geochemical stations for measuring the flow of CO2 degassing, atmospheric pressure, air temperature and soil humidity, located near the town of Pieve Santo Stefano (station name Fungaia).
In PHOTO 2 one of the stations near the town of Gubbio (station code TB01).
In PHOTO 3, a moment of the installation phase of a seismic sensor, in one of the wells (depth 202 m) drilled in the countryside of the town of Gubbio (station code TB02).
Scientific rationale - TABOO is a multidisciplinary geophysical observatory of INGV, designed for the study of active deformation processes along a system of extensional faults in the Northern Apennines and for the identification of earthquake preparation processes. The collection of high-resolution data from various disciplines is for TABOO the main tool for the description and modeling of the chemical-physical processes which, at different scales, control the faulting process and probably the genesis of earthquakes. For these reasons, since 2010, INGV has invested financial and human resources in the creation of a research infrastructure which, through permanent, detailed and multi-parameter monitoring of an active fault system, could allow to address fundamental aspects of tectonics and seismic source physics.
The monitored fault system is that of the Upper Tiber Valley (FIGURE 1), dominated in depth by the presence of a large normal fault with a low dipping angle (15°-20°), known in the bibliography as the fault Upper Tiberina (ATF). The ATF is a fault which due to its size (60x30km) could generate a strong earthquake, up to magnitude 7. The absence of an event of this size in the Italian historical seismicity catalogues, the particular geometry of the ATF, i.e. the low immersion angle below 30° which makes it an unfavorably oriented geological structure for reactivation with respect to the regional stress field, and the continuous and constant occurrence of small earthquakes, with occasional events of moderate magnitude (up to M 5.6; Gubbio , 1984), makes the Upper Tiber Valley a natural laboratory for studying the ways in which faults accommodate slip.
Furthermore, the area monitored by TABOO has been involved in recent decades by a considerable number of geophysical investigations, such as seismic prospecting and drilling of wells a few kilometers deep (up to 5 km), aimed at the search for hydrocarbons. These explorations allow to know, with a unique degree of accuracy in Italy, the lithologies present in the first kilometers of surface crust and the corresponding velocity field (at least for P waves), in 3-dimensions. These investigations also highlighted the presence of fluids (above all CO2) under pressure; this element further enriches the interest in this area, as the involvement of fluids in the genesis and evolution of seismicity is now ascertained, even if direct observations in this regard are still limited.
And it is through the data collected instead by TABOO, which along the ATF was documented for the first time in Italy, the occurrence of a slow earthquake (slow slip events) lasting almost 6 months and is always along the ATF that the modeling of the deformation profiles predicts that some portions of this large fault are in aseismic creeping (creeping).
The technological infrastructure - Through the contribution of various sections of the INGV (ONT - Rome1 - Palermo), a few dozen new sites have been equipped, to integrate the permanent measurement stations of the various national INGV networks, with instrumentation dedicated to multidisciplinary monitoring . In these remote stations are (when possible) co-located seismic sensors (3-component, short and/or long term and accelerometric), geodetic (GPS antennas and passive satellite speakers) and geochemical (Radon, CO2 and weather).
It is important to remember that some of these modern sensors (such as gaseous emissions meters and satellite diffusers) are prototypes entirely built at INGV.
All stations are powered by photovoltaic panels and are connected in real time via a dedicated system of Wi-Fi radio antennas to an INGV data acquisition centre, located in the Ancona office, from where they are then forwarded to the Rome office.
All the acquired data are made available to the whole scientific community (open access), nationally and internationally, through dedicated web portals and in standard formats.
Thanks to cutting-edge research projects in Europe and in the world, modern methodologies for installing both seismic and strain sensors are continuously developed with TABOO. One of these infrastructural implementation stages (occurred during the GLASS - ERC project), culminated with the installation of a series of probes in wells several hundred meters deep. This type of seismic antenna (seismic array), allows the study of the physics of the source of very small earthquakes and the monitoring of a wide spectrum of deformation transients.
Together with basic research, TABOO also represents an important tool for the creation of software products for the detailed and real-time analysis of multiple geophysical parameters. Once optimized, these software contribute to the institutional service activities of INGV, such as those of the National Earthquake Observatory and the Seismic Hazard Center, when these interface with Civil Protection, Civil Society and the Media.
TABOO in Italy and in Europe - TABOO is mapped among the leading research infrastructures in Europe, as one of the European Near Fault Observatories ( https://www.epos-ip.org/data-services/community-services-tcs/near-fault-observatories) , on the proposal of the EPOS project (European Plate Observing System; http://www.epos-eu.org/).
To date, TABOO therefore represents a natural laboratory for research, at the forefront of the international scene, where the best young scientists from all over the world can go to test their ideas on the processes of generating earthquakes. A virtuous process which, together with the qualitative increase in INGV's scientific research activity and the improvement of the effectiveness and efficiency of our observation system, also allows us to improve our country's international positioning in earthquake research.