When doing seismology on Earth, we use information from multiple stations to determine where a signal is coming from, using triangulation. On Mars, we only have one seismometer (InSight). Is this enough to get a (very) rough idea of where the marsquake occurred? If so, how is this done?
According to this paper by the InSIGHT seismometer ("SEIS") team (with a list of authors as long as your arm!), techniques combining data about the arrival times of various modes of seismic waves, the amplitude ("strength") of the waves, and surface waves that travel around Mars's globe more than once can determine the location of Mars quakes.
My reading of the paper is that the process isn't a straightforward calculation, but instead involves modeling of Mars's interior structure and wave propagation characteristics, adjusting the models until a coherent solution is reached. That "solution" includes the depth and geographic position of the quake's focus.