Synthetic Parameter Tests for Ambient Noise Tomography in the Vienna Basin

Ambient noise tomography has been applied worldwide to study the crust and uppermost mantle of the Earth. Phase velocities along the path connecting two stations are obtained from crosscorrelating the signals recorded at these stations at different periods. These periods typically lie within the second microseismic band between about 4 and 10 seconds, because a lot of noise is generated from ocean waves hitting the coast or interacting with the ocean floor at these periods. However, while it is preferable to work with these periods it is not always possible when interstation distances are too small (less than ~100 km). In such settings shorter periods need to be used for processing. Moreover, targeting shallow crustal structure also requires using periods shorter than 4 seconds, as longer period waves are not very sensitive to these depth ranges. We study the resolvability of crustal structure in the Vienna Basin area using ambient noise tomography. To that end we investigate the effects of crustal velocities on phase velocity sensitivity kernels and synthetic waveforms using crustal models and station distances which are representative of the Vienna Basin. Due to the lateral extent of the basin area as well as the currently available data from seismic stations we use distances ranging from 20 to 100 km, and periods from 0.5 to 3 seconds for our synthetic tests. Our aim is to establish what periods can be used for particular velocity structures and station distances, and later apply these to real data recorded at stations in or around the Vienna Basin.