Post by L Roebuck on Jul 22, 2006 8:10:32 GMT -5
Door County geology may have part in explosions
Investigators studying whether gas can travel in underground cracks
By Paul Brinkmann
pbrinkma@greenbaypressgazette.com
"Swiss cheese" geology could be one explanation for the mysterious leapfrog nature of Monday's deadly explosions in Ellison Bay, officials acknowledged Wednesday.
Door County and other parts of Northeastern Wisconsin are characterized by cracked limestone bedrock, shallow soil and sinkholes called "karst" features. Ancient beaches of pebbles and glacial stones lie underneath some shoreline areas like Ellison Bay.
On Wednesday, authorities said they are investigating whether gas could travel along cracks in the rock from one building to another. If that were true, and gas were leaking underground, it also could have collected in underground spaces before igniting. Three buildings that exploded are not adjacent to one another, and buildings in between were not affected.
"It's possible things could have traveled through the stony areas," Sheriff Terry Vogel said in a press conference Wednesday. He declined to reveal any more about the explosion source.
Mystery surrounding the source deepened when officials ordered the area evacuated again, saying another buildup of "explosive gas" was detected Tuesday night and Wednesday. Vogel declined to identify the gas, despite early speculation it could be propane. He added that carbon monoxide also was detected Wednesday.
Authorities haven't commented on speculation from Wisconsin Public Service spokesman Kerry Spees that installation of an electrical line could have damaged propane lines. Such a leak could have caused propane to pool or travel along underground pipes to a collection point where something ignited it, Spees suggested. He said WPS had a contractor performing such work late last week.
Investigators tested Brian Linden's nearby art gallery for gas regularly before ordering him and his family to evacuate again Wednesday.
"They've been testing for gas all over. That was reassuring. They were coming in and checking with monitors," Linden said. He was staying in a Fish Creek motel on Wednesday evening.
The blasts along Cedar Road destroyed one building, skipped one, hit another, skipped two buildings and hit another. If the geology were a factor, the source of the gas leak could be difficult to find.
"It's certainly a possibility that near-surface fractures could transmit the gases, but I don't know if that happened or not here," said Ron Stieglitz, a geologist with the University of Wisconsin-Green Bay who has published studies about karst geology in the area.
Another explosive gas, methane or "swamp gas," occurs in some wetland areas of Door County, Stieglitz said. He said a carbon monoxide buildup days after the explosions would be unusual.
"Any carbon monoxide from the explosions would have dissipated fairly quickly," Stieglitz said.
Door County's karst geology follows a fractured limestone ridge known as the Niagara Escarpment, which stretches from Niagara Falls around the Great Lakes and down into Wisconsin and northern Illinois. Bacteria and other contaminants sometimes enter groundwater through those cracks.
The sheriff remains in charge of the scene, assisted by the federal Bureau of Alcohol, Tobacco and Firearms and several Wisconsin agencies — the Fire Marshal's office, Emergency Management Agency and the state Department of Natural Resources.
Len Polczinski, a DNR waste supervisor, was in Ellison Bay on Tuesday to offer advice about disposing of debris. He recommended against holding debris in a local quarry. Debris from the buildings could have some hazardous materials such as asbestos, he said.
"I said it was a bad idea because of the fractured bedrock — the same thing that could have been a factor in the explosions," Polczinski said.
Article: www.greenbaypressgazette.com/apps/pbcs.dll/article?AID=/20060713/GPG0101/607130572/1207/GPGnews
Investigators studying whether gas can travel in underground cracks
By Paul Brinkmann
pbrinkma@greenbaypressgazette.com
"Swiss cheese" geology could be one explanation for the mysterious leapfrog nature of Monday's deadly explosions in Ellison Bay, officials acknowledged Wednesday.
Door County and other parts of Northeastern Wisconsin are characterized by cracked limestone bedrock, shallow soil and sinkholes called "karst" features. Ancient beaches of pebbles and glacial stones lie underneath some shoreline areas like Ellison Bay.
On Wednesday, authorities said they are investigating whether gas could travel along cracks in the rock from one building to another. If that were true, and gas were leaking underground, it also could have collected in underground spaces before igniting. Three buildings that exploded are not adjacent to one another, and buildings in between were not affected.
"It's possible things could have traveled through the stony areas," Sheriff Terry Vogel said in a press conference Wednesday. He declined to reveal any more about the explosion source.
Mystery surrounding the source deepened when officials ordered the area evacuated again, saying another buildup of "explosive gas" was detected Tuesday night and Wednesday. Vogel declined to identify the gas, despite early speculation it could be propane. He added that carbon monoxide also was detected Wednesday.
Authorities haven't commented on speculation from Wisconsin Public Service spokesman Kerry Spees that installation of an electrical line could have damaged propane lines. Such a leak could have caused propane to pool or travel along underground pipes to a collection point where something ignited it, Spees suggested. He said WPS had a contractor performing such work late last week.
Investigators tested Brian Linden's nearby art gallery for gas regularly before ordering him and his family to evacuate again Wednesday.
"They've been testing for gas all over. That was reassuring. They were coming in and checking with monitors," Linden said. He was staying in a Fish Creek motel on Wednesday evening.
The blasts along Cedar Road destroyed one building, skipped one, hit another, skipped two buildings and hit another. If the geology were a factor, the source of the gas leak could be difficult to find.
"It's certainly a possibility that near-surface fractures could transmit the gases, but I don't know if that happened or not here," said Ron Stieglitz, a geologist with the University of Wisconsin-Green Bay who has published studies about karst geology in the area.
Another explosive gas, methane or "swamp gas," occurs in some wetland areas of Door County, Stieglitz said. He said a carbon monoxide buildup days after the explosions would be unusual.
"Any carbon monoxide from the explosions would have dissipated fairly quickly," Stieglitz said.
Door County's karst geology follows a fractured limestone ridge known as the Niagara Escarpment, which stretches from Niagara Falls around the Great Lakes and down into Wisconsin and northern Illinois. Bacteria and other contaminants sometimes enter groundwater through those cracks.
The sheriff remains in charge of the scene, assisted by the federal Bureau of Alcohol, Tobacco and Firearms and several Wisconsin agencies — the Fire Marshal's office, Emergency Management Agency and the state Department of Natural Resources.
Len Polczinski, a DNR waste supervisor, was in Ellison Bay on Tuesday to offer advice about disposing of debris. He recommended against holding debris in a local quarry. Debris from the buildings could have some hazardous materials such as asbestos, he said.
"I said it was a bad idea because of the fractured bedrock — the same thing that could have been a factor in the explosions," Polczinski said.
Article: www.greenbaypressgazette.com/apps/pbcs.dll/article?AID=/20060713/GPG0101/607130572/1207/GPGnews