My latest data analyses suggest to me that your ear tone may have been linked with the following earthquake which reportedly claimed at least two lives:

2001/12/04 05:57:18 15.30S 72.59W 33.0 5.5
SOUTHERN PERU (from a NEIS data table)

I circulated an advisory for an earthquake in that area. Unfortunately, because of the amount of time that it took to evaluate the data the advisory was sent after the earthquake had occurred and before I saw it listed anywhere.

COMMENT: I will point out once again that the earthquake location determination procedure which I am using does appear to be producing good results at times with ear tone data like that.

These are my own opinions.