Objectives: The aim of this working group is to build a procedure to semi-automatically manage and analyze a seismic data stream, continuously recorded by several seismic stations connected to different acquisition systems.
The software packages will automatically determine arrival times and polarities of the P- and S-phases. By developing such procedure we will minimize the time needed to analyze data and to retrieve information on the target area. The retrieved dataset will be of high quality and intrinsically homogeneous due to the automated estimation of the reading errors, achieved through the auto-calibration of the picking system. The data retrieved will allow the study, almost in real-time, of seismicity distribution, seismic rate, b-value, Vp/Vs ratio to indirectly monitor fluid pressure changes, focal mechanisms and to acquire high-resolution images of the 3D seismic velocity structure. The whole procedure will be designed to be a standard for the analysis of future seismic field experiments, independently from the target site and will be applied off-line on the Task2 Messina strait data set.

Activities: The procedure will be modular. Distinct software packages will be written afresh and/or integrated to manage the separate steps of the data stream analysis and elaboration. Package 1: Seismic signal identification and association (seismic events definition); Package 2: Automatic Picking System and draft location; Package 3: high precision location; Package 4: data elaboration; Package 5: automatic results update. The different packages will be independently written and tested by different working groups.

Methodologies: Firstly, the procedure will have to identify the seismic signals related to P and S wavelets, by analyzing the variation of the STA/LTA ratio on each station data stream. This will determine the occurrence of seismic events based on an a-priori defined coincidence threshold (number of stations which recorded the event). Then, the procedure will precisely determine the arrival time of P and S onsets, related error estimation, P onsets polarity and the maximum amplitude for the magnitude calculation (ML). To get such high quality information we will implement the MannekenPix software package (MPX), already in use at INGV, to also determine polarities, pick S and calculate the maximum amplitude. By using the upgraded MPX we will automatically obtain, for both P and S picks, an estimation of the reading quality through an advanced statistic study of specific parameters mainly derived from the spectral analysis of the seismic signal and noise around the onsets. The weighting algorithm will be calibrated based on the comparison with a representative subset of high quality manual pickings. MPX will produce a good quality event location (1st location level) with standard location methods. The weighted P and S readings, the ML, and the locations by MPX, will be used to create maps of seismicity distribution, b-value, focal mechanisms, Vp/Vs ratio and to automatically update them. MPX initial locations will be also used to gain high precision earthquake locations through both linear and non linear location procedures.

Objectives: The goal of WP 1.2 is to obtain shallow imaging of the Tiber basin and ATF (down to 500-1000 m depth) by high-resolution (HR) and very high-resolution (VHR) seismic profiling across the western border of the basin.
Seismic survey is aimed at achieving two main targets. First, it would yield sub-surface information required to optimize drilling location and operation in the framework of the Project AIRPLANE. Second, HR and VHR reflectivity and tomographic images will fill the gap existing between geological field data and seismic commercial profiles. This would allow understanding of how the westernmost splays of the ATF imaged at depth (> 1-2 km) by oil the exploration data connect to the surface, and would provide valuable information on the Quaternary basin evolution and recent faulting activity. Moreover, HR imaging will provide useful constraints to re-interpret available commercial profiles.

Activities: Research activity includes six steps:

1. selection of the survey sites according to the local logistic and to previous information on the crustal structure. This activity will be carried out in collaboration with researchers of Perugia University (WP1.4-1.5);
2. acquisition of two HR and VHR profiles 2000 and 200-300 m long, respectively;
3. first-arrival traveltime picking and tomographic inversion;
4. CDP-processing of reflection data;
5. combined interpretation of HR and VHR Vp models and stack sections;
6. re-interpretation of commercial profiles constrained by results of the new seismic survey.

Methodologies: Seismic data will be collected with non conventional multi-fold wide-aperture geometry. A multi- channel acquisition device (216-channels) will record dense shots provided by a vibroseis (IVI Minivib) (HR data) and by a buffalo-gun (VHR data) source. Multi-scale reflectivity images will be obtained by CDP-processing of HR and VHR reflection data through PROMAX routines. Stack sections will be complemented by Vp images obtained by first-arrival tomography. This integration allows the enhancement of geological interpretation and the improvement of reflection imaging by using the tomographic velocity field in the CDP-processing. Both the new stack sections and available commercial profiles will be interpreted by industry software (LandMark-Seiswork).

Objectives: The aim of this working package is to integrate GPS data from regional GPS networks mainly developed for real-time positioning applications. In the Umbria Marche regions the Department of Civil Engineering of the University of Perugia have developed since 2005 the Labtopo GPS networks, which consist of about 20 continuous GPS stations (Prof. F. Radicioni). In this project we collaborate with the geodetic WP of the Perugia UR and integrate the daily rinex files of the Labtopo GPS network with the other CGPS sites coming from the INGV GPS (RING) and other GPS networks in a single processing scheme to obtain a homogeneous velocity field in terms of data processing and reference frame alignment. From this velocity field we will derive the distribution of the tectonic strain rate and the rate of strain accumulation of known active faults. We emphasize that this products constitute an essential component for an improved seismic hazard assessment.

Activities: The activities of this WP can be subdivided into the following targets:

1. Data collection and archiving. In collaboration with the Perugia UR we will collect all of the available data from the Labtopo GPS stations and archive in the central archiving facility in Rome;
2. Data processing with GIPSY-OASIS II and analysis of the time series;
3. Analysis of the GPS velocity field and derived products (strain rate, geodetic moment rate).

Methodologies: The raw daily GPS rinex files from the Labtopo network will be processed in an homogeneous processing scheme with the other GPS data coming from the RING and other public available GPS networks for a total amount of circa 350 GPS sites located in the Africa-Eurasia plate boundary and in the stable parts of the Nubia and Eurasian plates. We will use the GIPSY-OASIS software together with precise orbits and clock-files from the NASA Jet Propulsion Laboratory. The daily positions timeuncertainties.

Objectives: This WP will be focussed on the subsurface setting of the Tiber Valley through the interpretation of commercial seismic sections. The main goal is to reconstruct in detail the geometry of the Altotiberina fault, its splays and of the most significant stratigraphic markers. Among these, particular attention will be paid to the top of the basement, which can affect the distribution of the seismicity.

Activities: Concerning the subsurface data, the available seismic sections will be accurately reinterpreted, calibrated with the boreholes and depth converted on the basis of the most accurate and realistic velocity model. The geological sections will be balanced with special emphasis to the balancing of the extensional structures with the aim of also evaluating the long-term slip-rates. On the basis of the transversal sections, a longitudinal section will be built up. Starting from the geological sections, isobath maps of the Altotiberina fault, of its splays and of the top of the basement will be constructed.
In the final part of the project, through the interaction with the other UR, a comparison will also be made between:

1. long-term slip-rates along the faults, acquired by surface geological data and by the balancing of the subsurface geological sections;
2. subsidence and uplift rates, obtained from the surface geology and geomorphology;
3. short-term movements (from GPS).

Methodologies:

1. geological interpretation of seismic sections;
2. depth conversion of the interpreted seismic sections;
3. balancing of the geological sections.

Objectives: This WP will be focussed on the definition of the geological and geomorphological evolution of the Tiber valley from Perugia to Cittˆ di Castello providing a new cartography drawn with homogeneous criteria.

Activities: The outcropping Plio-Quaternary deposits in the high Tiber valley and the faults cutting these sediments will be mapped. During the fieldwork, the most significant stratigraphic sections will be analysed. The interpretation of aerial photographs will provide a support for both the geological and geomorphological map and for the recent and active tectonics indicators. Automatic procedures of DEM analysis will also be applied to identify active tectonic markers. The gathered and interpreted data will be summarized in a scheme of the stratigraphic relationships of the Plio- Quaternary successions and geological and geomorphological map at the the scale 1:100.000. The data will also be used in order to estimate the long-term uplift/subsidence rate (between 1 and 1000 kyrs).

Methodologies:

1. geological and geomorphological mapping;
2. aerial photographs interpretation;
3. automatic and semi-automatic digitl terrain models analysis .