In Mona Van Duyn's "Earth Tremors Felt in Missouri", what is the "quake last night"?

The “quake last night,” which the speaker refers to in
line 1, may involve a personal problem, or else a problem in the attitude of the
listener toward the speaker—we are not told the exact circumstances. But a problem was
expressed, and to the speaker it has assumed the magnitude of “earth tremors felt in
Missouri.” Depending on the location of the speaker and listener, Missouri may be as far
as halfway across the country. Personal circumstances, in other words, become earth
shaking, and what might seem to be no more than a “pebble” to the outside world has
planetary importance, even going so far as to encompass and include “the sun.” Ordinary
and everyday life thus becomes cosmic. This elevation of the personal is reminiscent of
the relationships described by Donne in a number of his love
poems.