Visitor to PoreLab NTNU: Welcome to Professor Wojciech Debski

Professor Wojciech Debski, head of the department of Theoretical Geophysics at the Polish Academy of Sciences, will visit PoreLab on January the 18th and will give a seminar entitled “Time Reversal method, from mathematical principles to waveform analysis applications”. The lecture will take place at our PoreLab premises (PTS2, second floor) on January the 18th from 13 to 14.


Building  knowledge on surrounding world requires information about it. This almost trivial statement  gains a much deeper sense in cases when we cannot infer thought information by  direct measurements. It  happens quite often.  In such a case we  need to refer to a kind of “indirect measurements’’  and infer thought information from other available observational data. This  more complex approach is often referred to as “inverse theory’’. In this talk I will present the modern inverse  method  called Time Reversal Mirroring (TRM) which provides an efficient way of inferring information from recorded waves provided governing  equation is a linear, hyperbolic PDE.   From the physical point of view the method is based on two basic symmetries of underlying equation(s): time reversal and source-receiver reciprocity.   They  allow  to construct an extremely  efficient  numerical algorithm for  analyzes of complex time series data in searching for “hidden’’ information about waves source and/or medium properties.

My talk  begin from basic mathematical principles upon which the TRM method is build up.    Next I will give a short overview of  idea of “inverse problems’’ and how TRM fits to this framework.  In the second part I will discuss the particular applications of TRM method, namely the source location task and (eventually) tomography imaging