Mary Jane,
The far-field earthquake triggering concept is that when a great quake occurs in
one are of the world, the most likely areas to see "aftershocks" are those regions
where seismic energy from the great quake is concentrated by internal reflection
of waves or by factors relating to spherical geometry.
Regions at plate boundaries are generally seismically active because the
plates are sliding past each other constantly. This adds a continuous strain
which may be relieved by random events or by triggered events where a sudden
input of energy is the final factor before the earthquake. Because earthquakes
in such regions are commonplace, it is more difficult to see relationships such
as far-field triggering.
Intra-plate zones, such as New Madrid may be areas where such relationships
are more easily seen because the earthquakes in such areas are rarer and the
background noise level is much reduced. The same mechanism applies, however,
a sudden influx of energy and ground motion into the region, so there is no inherent
reason to believe that regions such as New Madrid would be more likely to
respond with far-field earthquakes than other similarly located areas whether
on plate boundaries or not.
By the way NEIS is now showing today's earthquake in New Madrid as a Mb 3.1. If
this magnitude is correct, it will be the largest earthquake in the New Madrid region
since a Ml 3.9 on Oct. 21, 1999.
Sounds like a bit of price-gouging on the part of your insurance company. As far
as I am aware there has been no reappraisal showing higher seismic risk in the
area in the past few years.