The Mudcat Café TM
Thread #139993   Message #3217213
Posted By: GUEST,TIA
02-Sep-11 - 03:02 PM
Thread Name: BS: Global Warming- CERN says not man-made
Subject: RE: BS: Global Warming- CERN says not man-made
EBarnacle-
You said the key word "semi-structural". The stuff we extract (water, oil, gas) resides within the porosity of the host rock. If the pore fludis are supporting some of the wegith of the overburde, yes, extraction leads to subsidence...the Central Valley of California is a perfect example of widespread and dramatic (>30 feet) subsidence due to water withdrawal.
In many cases, the overburden is supported by the grains in the rock/sediment, so extraction does not produce subsidence (e.g. nearly all shale gas).