I have a vague recollection from the the previous GC sinkhole of a report that a storm-water relief tunnel had been drilled under the city in these unconsolidated volcanic ash (which is what is shown in the photos forming the walls of the sinkhole) and both the tunnel and the concrete casing were built by the lowest bidder and were failing offering ingress to storm and sewer water passing down the tectonic fissures which can also be seen in the walls of the shaft. That could be completely spurious information but it is what I seem to remember and would explain the depths of the two pits being (nominally) the same. It could also be that someone just threw out that number (100 meters being a nice, round number) and the reporters made it official. --Ediger
On Fri, Jun 4, 2010 at 11:05 AM, Mark Minton <mmin...@caver.net> wrote: > Several sources gave the depth of the new sinkhole as 330 feet (100 > meters), the same as the previous one that opened up not far away in > Guatemala City a couple of years ago. Who knows whether it was actually > measured or they're just guessing, maybe using the same figure because the > two look a lot alike. These were most likely caused by soil piping due to > leaking water and sewer mains, so they could logically be the same depth, > reaching down to whatever level the water drained away on. Given that it > looks like the walls are essentially sand, I wouldn't expect open passage to > go very far, or stay open very long. > > Mark Minton > > At 10:43 PM 6/3/2010, David wrote: > >> >> http://www.csmonitor.com/var/ezflow_site/storage/images/media/images/csm-photo-galleries-images/in-pictures-images/guate-sinkhole/002/8062435-1-eng-US/002_full_600.jpg >> >> The new Guatemala sinkhole shown above is about 20 meters across, so >> the depth to the very bottom looks like 150 meters plus. >> >> There seems to be a canyon down there on top of the breakdown pile, so >> that would suggest something. >> >> Anything you rig to could fall off into the sinkhole, or something >> could fall and cut the rope. >> >> Maybe a helicopter rappel would be safer? >> >> Would be best to lower a video camera down first. Right ? >> > > Please reply to mmin...@caver.net > Permanent email address is mmin...@illinoisalumni.org > > --------------------------------------------------------------------- > Visit our website: http://texascavers.com > To unsubscribe, e-mail: texascavers-unsubscr...@texascavers.com > For additional commands, e-mail: texascavers-h...@texascavers.com > >
