Forensic Seismology

We categorize unconventional applications of seismic recordings under “Forensic Seismology”. Non-earthquake mechanical activities are recorded by sensitive seismometers. Extracting information on such activities out of wiggles requires the use of strict scrutiny. Analysis of these non-earthquake sources can often give information that is important to investigative agencies and insurance companies. The publicized scenario for the loss of Kursk submarine on 12 August 2000 is derived from forensic seismology.

In SeisAnalysis we have the required expertise and experience to extract such information. Often such information remains unexplored. The Chelyabinsk meteor exploded over Russia on 15 February 2013. This was the largest known object entering the Earth’s atmosphere since the 1908 Tunguska meteor. The magnitude of this impact was estimated as 4.2 based on analyzing the seismic energy radiated from this event. In SeisAnalysis, we extracted the following information from the recording of ARU seismic station. The station is about 320 km from the impact point and here we use only one broadband vertical component.

There were 3 main sources of cultural noise in the nearby area.
The sources, most likely firms, were operating in narrow frequency ranges of 4.1, 5.05, and 8.15 Hz.
Upon meteorite impact, the firm with the dominant frequency of 5.05 Hz was immediately turned off.
About 10 minutes later the source was turned on.
The halting process was gradual; the source was spinning for about a minute before coming to a total halt.
The restarting process was sharp.
The other two firms continued their operation during the meteorite impact.