Historically, one of the weapons of civil unrest is fire. In the case of fire moving through a highly-populated area, bugging out would be a distinct possibility, so being able to grab some pre-gathered supplies and having a place to run to
Definitely agree. Most of the damage from the 1906 San Fran. earthquake came AFTER the quake, from fires that raged for days.
Looking at more recent quakes, such as the 89 S.F., or the 92 Northridge, lots of damage was either initial, or aftershocks knocking down previously weakened structures.
The moral is, if you worry about New Madrid, just recall that it won't hit once. Check out some of the CA preparedness sites (ARC, city/county fire department preparedness pages, etc), for more info on how to prepare specifically for this threat.
As to the other situations, listen to what folks here have already written.