Concord Planning Commission and the City Council held hearings and appeals on the subject. Then, the city's own engineering study revealed that the base was not adequate to support the Smokestack during an earthquake. The report included the numbers of people who would be injured or killed, depending on which way the Smokestack fell. To summarize:
6 February 2009
• The smokestack is very vulnerable to overturning (resisting force of less than 48% of the seismic overturning force);
• 7% in 10 years or 47% in 50 years probability of overturning, not including higher earthquake magnitudes from earthquake fault lines farther than 22 miles from the smokestack, and not including potential collapse of smokestack due to failure of the smokestack shell due to the documented degradation of concrete and steel reinforcements; and
• The estimated 374 persons at risk, $8 million in property value at risk, and another $1.5 million cleanup cost if the smokestack collapses.
Figure 1 - Aerial View-Cowell Stack - Collapse & Debris Hazard Zones
Cowell Historical Society