The Elginfield Infrasound Array (ELFO)
Interesting (non-meteoric) Events detected by ELFO
Imperial Oil Refinery Explosion, December 13, 2006
In the early morning hours of December 14th, residents of Sarnia, Ontario were awakened by a loud, thunderous explosion from one of the hydrocracking units from the Imperial Oil Refinery located at the southern border of the city (42.950°N, -82.416°W, Fig. 1a). The 18,000 barrel/day unit was responsible for processing and upgrading heavy oils unsuited for gasoline or diesel fuel. The ensuing fire (Fig. 1b) was contained to the single unit. Located at a range of 93 km from the Elginfield Infrasound array (ELFO) the infrasonic blast was observed at 8:02:49 UT (BkAz: 257.1° ± 0.6, Vapp: 341 ± 1 m/s) consistent with a direct tropospheric path (Figure 1c). The observation assisted investigators and structural engineers by constraining the time of the explosion to ~07:56 UT (2:56 am local EST), and its estimated yield at between the equivalent of 5 – 10 tons of TNT using amplitude and period measurements (Whitaker 1995).
No damage (broken windows etc.) to the nearby buildings, nor injuries to on-duty workers were reported. The cause of the explosion was not released.
Figure 1a (larger image) and Figure 1b (smaller image)
The observed blast