Abstract

The Vp/Vs-ratio gives insight into material properties such as rock composition, fluid content, and fracture orientation. A method for in-situ Vp/Vs-ratio measurement was proposed by Lin and Shearer in 2007, that uses differential travel times for Vp/Vs -ratio estimation. However, this method is biased due to violations of assumptions such as coincident raypaths. 

A new method called VREEC (Velocity Ratio Estimation within Earthquake Clusters) was developed by Ostermeier (2025) to overcome the limitations by including ray angle information. This master's thesis now has the goal of applying the VREEC method to the geothermal site of Rittershoffen (France), as well as to test its limitations for very shallow earthquakes with depths of less than 5 km.  

Presented here are the synthetic tests based on real geometry to determine the limits of the resolution, and preliminary results for Vp/Vs-ratio estimation of the recorded data.