Wayne N. EdwardsWayne N. Edwards11, Peter G. Brown, Peter G. Brown11, David McCormack, David McCormack22

1Department of Physics and Astronomy, University of Western Ontario, London, Ontario, N6A 3K7, Canada. 2Natural Resources Canada, Ottawa, Ontario  K1A 0E8, Canada

Sarnia, Ontario: December 13, 2006Sarnia, Ontario: December 13, 2006Imperial Oil Refinery ExplosionImperial Oil Refinery Explosion

Ilderton, Ontario: April 24, 2007Ilderton, Ontario: April 24, 2007Methamphetamine Lab ExplosionMethamphetamine Lab Explosion

Toronto, Ontario: August 10, 2006Toronto, Ontario: August 10, 2006Propane Storage Facility ExplosionPropane Storage Facility Explosion

Kincardine, Ontario: August 1, 2008 – Mysterious Explosions over Kincardine, Ontario: August 1, 2008 – Mysterious Explosions over Lake HuronLake Huron

In the early morning hours of December 14In the early morning hours of December 14thth, residents of Sarnia, , residents of Sarnia, Ontario were awakened by a loud, thunderous explosion from one of Ontario were awakened by a loud, thunderous explosion from one of the hydrocracking units from the Imperial Oil Refinery located at the the hydrocracking units from the Imperial Oil Refinery located at the southern border of the city (42.950°N, -82.416°Wsouthern border of the city (42.950°N, -82.416°W, Fig. 1a). The 18,000 Fig. 1a). The 18,000 barrel/day unit was responsible for processing and upgrading heavy barrel/day unit was responsible for processing and upgrading heavy oils unsuited for gasoline or diesel fuel. The ensuing fire (Fig. 1b) was 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 contained to the single unit. Located at a range of 93 km from the Elginfield Infrasound array (ELFO) the infrasonic blast was observed at Elginfield Infrasound array (ELFO) the infrasonic blast was observed at 8:02:49 UT (BkAz: 257.18:02:49 UT (BkAz: 257.1°° ± 0.6, V± 0.6, Vappapp: 341 : 341 ± 1 m/s) consistent with a ± 1 m/s) consistent with a

direct tropospheric path (Figure 1c). The observation assisted direct tropospheric path (Figure 1c). The observation assisted investigators and structural engineers by constraining the time of the 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 explosion to ~07:56 UT (2:56 am local EST), and its estimated yield at between the equivalent of between the equivalent of 5 – 10 tons of TNT5 – 10 tons of TNT using amplitude and using amplitude and period measurements (Whitaker 1995).period measurements (Whitaker 1995).

No damage (broken windows etc.) to the nearby buildings, nor injuries No damage (broken windows etc.) to the nearby buildings, nor injuries to on-duty workers were reported. The cause of the explosion was not to on-duty workers were reported. The cause of the explosion was not released.released.

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1Department of Physics and Astronomy, University of Western Ontario, London, Ontario, N6A 3K7, Canada. 2Natural Resources Canada, Ottawa, Ontario  K1A 0E8, Canada

(a)(b)

At ~10pm an explosion from a rural farm house at 11543 Ilderton Road At ~10pm an explosion from a rural farm house at 11543 Ilderton Road (43.0566(43.0566°°N, 81.4411N, 81.4411°°W) was reported by area residents. The resulting W) was reported by area residents. The resulting fire engulfed the home as dozens of regional volunteer firefighters fire engulfed the home as dozens of regional volunteer firefighters fought to contain it. Police remarked that the two-storey home had its fought to contain it. Police remarked that the two-storey home had its entire north and rear walls blown outward revealing the interior of the entire north and rear walls blown outward revealing the interior of the home before the fire had ignited. One man was rescued and taken to home before the fire had ignited. One man was rescued and taken to hospital for burns and smoke inhalation, while his wife and two children hospital for burns and smoke inhalation, while his wife and two children escaped uninjured. The family dog was killed. While house fires are not escaped uninjured. The family dog was killed. While house fires are not unusual, these reports of an explosion prompted a search for unusual, these reports of an explosion prompted a search for infrasound from the event for confirmation. At 2:09:30 UT (10:09:30 infrasound from the event for confirmation. At 2:09:30 UT (10:09:30 EDT) a short, 30 second impulse from the direction of the home EDT) a short, 30 second impulse from the direction of the home (195.4(195.4°) was discovered (Fig 2). From period and amplitude °) was discovered (Fig 2). From period and amplitude measurements of the pulse the explosion was equivalent to measurements of the pulse the explosion was equivalent to ~160 lbs ~160 lbs of equivalent TNTof equivalent TNT (Whitaker 1995). (Whitaker 1995).

Investigations discovered the explosion was caused by ignition of Investigations discovered the explosion was caused by ignition of chemicals in the basement due to an illegal drug and marijuana lab. chemicals in the basement due to an illegal drug and marijuana lab. The man and wife were charged with: arson with disregard for human The man and wife were charged with: arson with disregard for human life, arson with negligence, possession and production of drugs and life, arson with negligence, possession and production of drugs and marijuana for the purpose of trafficking. marijuana for the purpose of trafficking.

At dusk on August 10, 2008 the Downsview region of the city of Toronto, At dusk on August 10, 2008 the Downsview region of the city of Toronto, Ontario was rocked by two powerful explosions from the Sunrise Propane Ontario was rocked by two powerful explosions from the Sunrise Propane Industrial Gases Storage Facility south of the Downsview airport Industrial Gases Storage Facility south of the Downsview airport (43.733°N, -79.473°W(43.733°N, -79.473°W, Fig. 3b). This resulted in a fire that engulfed the Fig. 3b). This resulted in a fire that engulfed the entire facility, causing several more powerful explosions as propane entire facility, causing several more powerful explosions as propane tanks erupted. Surrounding residential homes were damaged as windows tanks erupted. Surrounding residential homes were damaged as windows shattered and doors were taken off hinges. The explosions caused the shattered and doors were taken off hinges. The explosions caused the evacuation of thousands of residents over 1.6 km wide area and shut evacuation of thousands of residents over 1.6 km wide area and shut down al 16 lanes of nearby HWY-401 (Canada’s busiest highway). The down al 16 lanes of nearby HWY-401 (Canada’s busiest highway). The fireball and explosions could be seen for many km’s as it rose more than fireball and explosions could be seen for many km’s as it rose more than 200 m into the sky. One firefighter and a Sunrise employee were killed.200 m into the sky. One firefighter and a Sunrise employee were killed.

ELFO observed several arrivals from the multiple explosions (Fig. 3a). ELFO observed several arrivals from the multiple explosions (Fig. 3a). Azimuths and time delays are consistent with direct topospheric arrivals Azimuths and time delays are consistent with direct topospheric arrivals for the two main explosions, while a low amplitude wavetrain small for the two main explosions, while a low amplitude wavetrain small explosions/fire) can be seen afterwards for ~9 min.explosions/fire) can be seen afterwards for ~9 min.

Around 11pm EDT on July 31Around 11pm EDT on July 31stst, 2008, residents of Kincardine, Ontario were awakened by two loud, thunderous bangs , 2008, residents of Kincardine, Ontario were awakened by two loud, thunderous bangs emanating from somewhere over Lake Huron. The sounds, as reported by residents, were apparently loud enough to rattle emanating from somewhere over Lake Huron. The sounds, as reported by residents, were apparently loud enough to rattle windows and objects on walls. Initial guesses as to the source of the “thunder” were (1) a perseid meteor, (2) an accident windows and objects on walls. Initial guesses as to the source of the “thunder” were (1) a perseid meteor, (2) an accident at a regional nuclear power plant, (3) nearby salt mine blasting (4) supersonic aircraft. ELFO infrasound showed that two at a regional nuclear power plant, (3) nearby salt mine blasting (4) supersonic aircraft. ELFO infrasound showed that two blasts were observed at 02:12:30 UT along with a series of inaudible phases (Fig. 4a) arriving from 315-323blasts were observed at 02:12:30 UT along with a series of inaudible phases (Fig. 4a) arriving from 315-323° (V° (Vappapp: 348-: 348-

353 m/s)353 m/s). These observations (along with all-sky cameras) ruled out a meteor source, as well as operations at the Bruce . These observations (along with all-sky cameras) ruled out a meteor source, as well as operations at the Bruce Nuclear Power Plant, while Goderich salt mine logs eliminated it as a source. The impulses were also observed seismically Nuclear Power Plant, while Goderich salt mine logs eliminated it as a source. The impulses were also observed seismically as ground coupled acoustic waves around South Western Ontario and Northern Michigan (Fig. 4b). From observed back as ground coupled acoustic waves around South Western Ontario and Northern Michigan (Fig. 4b). From observed back azimuths and particle motions observed at seismic sites, the source of the two blasts was identified as originating from an azimuths and particle motions observed at seismic sites, the source of the two blasts was identified as originating from an area in Northern Michigan (45.04area in Northern Michigan (45.04±0.12±0.12°°N, 83.62±0.21N, 83.62±0.21°°W, 44.905±0.061W, 44.905±0.061°N°N 83.492±0.047°W) with a probable origin time of 83.492±0.047°W) with a probable origin time of ~2:59 UT with explosive yields between ~2:59 UT with explosive yields between 2-3 tons on TNT2-3 tons on TNT (Whitaker 1995), consistent with quarry-type explosions (Whitaker 1995), consistent with quarry-type explosions. . Wurtsmith AFB and restricted airspace R-4207 lie near this region, but AF activities ceased in 1993 and local airport radar Wurtsmith AFB and restricted airspace R-4207 lie near this region, but AF activities ceased in 1993 and local airport radar reported no aircraft in the area at the time. The Alpena open pit calcite mine, however, lies only 18 km NE. If the sounds reported no aircraft in the area at the time. The Alpena open pit calcite mine, however, lies only 18 km NE. If the sounds were blasts from the mine, seismic phases should have arrived at the stations at ~03:01 UT. Such arrivals can be readily were blasts from the mine, seismic phases should have arrived at the stations at ~03:01 UT. Such arrivals can be readily identified at several stations. It appears that due to propagation conditions, Kincardine lay near a convergence of sound identified at several stations. It appears that due to propagation conditions, Kincardine lay near a convergence of sound propagating from explosions at the Alpena mine (a known source of other inaudible signals at ELFO).propagating from explosions at the Alpena mine (a known source of other inaudible signals at ELFO).

Figure 1

#3 Enduring wavetrain#2 Explosion#1 Initial Explosion1 km1 km (c)

Duration

BASO

BRCO

BMRO

BWLO

CLWO

ELFO

TOBO

AAM

Seismically coupled acoustic wave

Figure 2~30 second pulse (above) of the explosion which destroyed an Ilderton house (right).

Audible “Bangs” (coupled seismically below)

Inaudible “bangs”

Subsequent “rumble”

Figure 3 Hwy 401

Dow

nsview Airport

Sunrise Propane Facility

Affected Area

Figure 4

(b)

(a) 3-Sunrise Propane

2-Meth. Lab1-Imperial Oil

4-“Mystery Blasts”4-“Mystery Blasts”

Lake Huron

Lake Erie

Georgian Bay

R-4207

Alpena Calcite Open-pit MinesAlpena Calcite Open-pit Mines

ELFO

Wurtsmith AFBWurtsmith AFB

AAM

CLWO

TOBO

BASO

BRCO

BMRO

BWLO

Yield estimates for the two main Yield estimates for the two main explosions give:explosions give:

46-128 & 118-125 tons of eq. TNT46-128 & 118-125 tons of eq. TNT

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