There were two earthquake west of Trinidad, Colorado area today at about 37N 104.7W.
These were Ml 3.5 and Ml 3.4. These were the largest within 50 km of this location
since August 1, 1996 and the second and third largest in 28 years since September
23, 1973 when a swarm (maximum size Ml 4.0) occurred NE of this location.
Two other earthquakes have been recorded in this area in this magnitude range
- on Oct 3, 1966 (Ml 4.0) and June 6, 1963. And yes, these were 102 degrees
from the New Zealand mainshock, like yesterday's unusual quakes. Kind of suggests
some sort of triggering, at least to me.
I use a multitude of sources for earthquake data. There are many local sources
which list earthquakes on the web including the USGS, MEDNET, Red Puma,
GSSC, for teleseismic quakes, and groups of local networks like SCSN, NCSN,
PNSN, MBMG, UUSN, NESN, USBR, etc. for data on local U.S. earthquakes.
Similar groups exist for most countries of the world now. Data is usually available
more rapidly from local networks than from the USGS, and is of higher quality
for local events. However, USGS is a good source to check local data against.