30 Novembre 2018, 14h30, IUEM Amphi A
Passive seismics as a tool for crustal exploration:
performances, key-achievements and future developments.
Exploration of the Earth’s crust is often based on active seismic data, but in complex geology settings active seismic imaging can face serious problems. Alternative exploration techniques can help to reduce risks for building accurate Earth’s models. In the last decade, the analysis of passive seismic data, i.e. natural seismicity and seismic ambient noise (collectively called Passive Seismic Techniques, PST), have been widely used to investigate the subsurface. In particular, the propagation of seismic waves generated by teleseismic earthquakes, i.e. earthquakes occurred more than 3000 km from the study area, have been exploited to constrain the fine details of the crustal structure and elasticity. Receiver Function (RF) analysis is a PST adopted in academia that makes use of teleseismic waves to image the structure of the crust. RF analysis has been applied for both deep and shallow crustal imaging, e.g. from Moho to basin mapping. Moreover, RF analysis can be used to locate anisotropic materials at depth, a tricky target for active seismics.
In this talk, I will briefly introduce RF analysis, measuring the performance of this PST against the results obtained by active seismic survey and borehole lithostratigraphies. I will show key-applications of RF analysis for crustal exploration, like: (a) how joint interpretation of passive and active seismic data can be useful to improve our knowledge of the subsurface at different depth-levels; (b) how RF analysis can be used to explore the presence of anisotropic materials in geothermal fields, indicating anomalous PT conditions; and (c) how teleseismic waves can used to improve sedimentary basin investigations. Finally I will discuss the cons of the PSTs and the future development of the research in this area.