Who said that?
The hoover dam is in an elevated risk area, but not along a major fault line.
Now you are shifting from ecological and climate data to geotechnical and seismic... not usually in the realm of "mother nature"
You are pulling 9.1 out of your ass on that one.
You were the one that brought up engineering and Hoover Dam. Now you bitch at me because I commented on your ignorance about Hoover Dam? If you're going to bring something into a discussion, you ought to know what you're talking about first. In terms of the seismic engineering of the Hoover Dam built back in the 30's. Let alone what they knew about seismicity and plate tectonics back then, As for a magnitude 9.0 - 9.1 quake didn't we have one in Japan a few months ago?
"ABSTRACT
Large dams, especially concrete dams, have been designed against earthquakes since the
construction of Hoover dam in the 1930s. The design criteria and methods of analysis used in
those times are outdated today and the actual seismic safety of these structures is not known
in view of todays requirements. Earthquake action was usually taken into account pseudostatically,
through an inertia force characterized by a seismic coefficient. Since 1989 the
ICOLD guidelines consider two levels of seismic loading, namely the operating basis
earthquake (OBE) and the safety evaluation earthquake (SEE). Various methods of dynamic
analysis are now available to predict the dynamic response of dams to strong ground shaking.
Rehabilitation planning and design must take into account these developments, even in
regions of low seismicity and assess whether seismic upgrading of a particular dam is
necessary from a seismic safety point of view."
http://www.poyry.ch/linked/en/aboutus/Current_seismic_safety_requirements_for_large_dams_0408.pdf