Informant38

Previously, Herrin and Teplitz speculated that it would be possible to search for seismic events that might indicate passage of strange quark matter (also known as nuclearites) through the Earth because such events would have a distinct seismic signal - a straight line.
This seismic signature would be caused by the large ratio of the nuclearites speed to the speed of sound in the Earth. It was estimated that the strange quark matter might pass through the earth at 400 km per second (250 miles per second), 40 times the speed of seismic waves.
Data collection halted
The team also determined that the minimum requirement for detection of a nuclearite would be detection of its signal by seven monitoring stations.
The researchers latest findings single out two seismic events with the linear pattern they were looking for.
In two cases, the arrival times and forms of seismic waves at nine far-flung stations pointed to linear bursts of energy. The ruptures ripped through the planet at hundreds of kilometres per second rather than fracturing only near the surface, as typical earthquakes do.
One event occurred on 22 October 1993, when, according to the researchers, something entered the Earth off Antarctica and left it south of India 0.73 of a second later.