And in remembering another paper... it wasn't about a black hole but rather quark matter...

Two Seismic Events with the Properties for the Passage of Strange Quark Matter Through the Earth - http://www.geology.smu.edu/~dpa-www/sqm/pdf/sqm_lanl.pdf

It looks at pairs of seismic events that trace line through the earth and are timed correctly.

> Two sets of reports were found in the 1993 database that fit all the criteria for a linear source. The model and residuals (observed minus predicted arrival times) for the first event are given in Table 1. The RMS residual is 0.73 sec. This RMS value would indicate a good fit for a well-located earthquake.

A BBC article about the paper: http://news.bbc.co.uk/2/hi/science/nature/2502755.stm