The IBERARRAY seismic network: an example of new generation broad-band array at a regional scale

Abstract

One of the main experimental components of TOPOIBERIA, a multidisciplinary large scale research project aiming to study the links between the deep and superficial processes in the Iberian Peninsula, is the deployment of the IBERARRAY seismic network. A dense array (60x60 km) of new generation data-loggers equipped with broad-band seismometers will cover Iberia and North Morocco in three successive deployments, each lasting for about 18 months. The first leg, deployed in 2007, covers the southern part of Iberia (35 stations) and northern Morocco (20 stations). A standard procedure has been established to recover and process the data; field teams collect the recorded hard disk on the field and send data and metadata to a central processing center, where raw data is collected and stored and a quality control checking is performed. This include a systematic inspection of the experimental parameters (batteries charge, thermal insulation, time adjustments, geophone leveling etc), the visual verification of the seismic waveforms and the analysis, using power density spectra (PSD), of the noise level of each station. All this information is disseminated between the research teams involved in the project using a dedicated website and the continuous seismic data is made accessible through FTP and CWQ servers. Some of the nodes of the theoretical network are covered by permanent stations of the national broad-band network (IGN) or other networks operating in the region (IAG-UGR, ROA). Data from those stations will also be integrated to the Iberarray database. This Iberarray network will provide a large database of both waveform and catalogued events, with an unprecedented resolution. Earthquake data at local, regional and teleseismic scales will be analyzed using different methodologies. The first result would be an increase in the accuracy of the location of regional seismicity and the determination of focal mechanisms. A special emphasis will be attributed to seismic tomographic techniques using travel times and waveforms of P and S arrivals at different scales as well as surface waves, using dispersion measurements as well as studies dealing with background/ environmental noise. In addition, receiver function analysis for seismic imaging of deep lithospheric features and splitting analysis of shear-wave arrivals will also be developed