The analysis of data recorded by sensors installed in boreholes has yielded important information for numerous applications in the Engineering and Seismological communities. Borehole arrays can help estimate small-strain properties of the shallow layers and also improve our understanding of strong ground motion, including non-linear soil behaviour and material properties, as well as liquefaction phenomena. Strong and weak motion data from depths of a few meters down to a few kilometers can give information on the mechanisms behind site amplification (such as basin-edge and other complex site effects related to the shallow geological structure) and site attenuation (such as anelastic attenuation, Q, and the high-frequency decay parameter, kappa; the latter may also bear on seismological problems such as stress-drop). Downhole arrays are also the best source of data for estimating input ground motion at bedrock level. When combined with arrays installed in nearby buildings, the joint data analysis allows a comprehensive study of wave propagation through the shallow layers and interaction with the building.

This session aims to bring together the Engineering, Seismological, and Geophysical communities and create a platform for discussion and exchange concerning borehole arrays, data, and applications. We welcome contributions from all aspects of borehole data analysis, including, but not limited to: interferometry, material properties in the linear and non-linear range, site response, amplification, and attenuation. We encourage novel and hybrid applications of vertical arrays, including coupled subsurface-and-superstructure arrays. We also seek to hear from those installing new arrays and compiling new datasets and public databases of downhole data, and to discuss exciting new possibilities for applications.