Forensic Investigation of a Probable Meteor Sighting Using USArray Acoustic Data

Abstract

In the early evening of 26 November 2013, the residents to the west of the city of Montreal, Canada, were witness to an unusual event in the region’s heavily overcast and snow‐filled skies (Fig. 1). Just prior to 20:00 EST (01:00 UTC on 27 November) residents began to report seeing a bright, transient, and distinctly blue flash in the sky. This flash was bright enough to briefly illuminate the otherwise overcast and featureless skies of the region. Several minutes later, this flash was accompanied by an explosive sound, rumbling, and apparent tremors as described by many eyewitnesses, including at least one pilot of an airborne commercial aircraft (Spears, 2013). Many of these eyewitnesses quickly turned to social media to express their observations and surprise. Not long after, news media were reporting on the event and looking for any confirmation from expert and trustworthy sources on the event’s occurrence and its source, as no video or photographs of the event had surfaced, likely because of the heavy cloud cover over the region. Figure 1. Map of regional Canadian and American seismic networks and USArray Transportable Array (TA) seismoacoustic stations near Montreal, Quebec. Only a few seismic instruments recorded the meteor event reported by the public on 27 November 2013 (gray diamonds), yet detections were plentiful on USArray infrasonic and acoustic sensors (black stars). Using TA network wide‐beam techniques, the event is localized to have originated to the west (hexagram star) of station G58A, where the largest amplitude ballistic signal was observed. Further ballistic shock‐wave observations from the meteoroid’s entry coupled with eyewitness reports help constrain a general north–south trajectory for the meteor (black arrow), whereas infrasound from its apparent breakup propagated and remained detectable for several hundred kilometers to the southeast (gray arrow). The prospect of significant meteor events over populated centers is …