SASO's Top Ten List

The following list is continually updated. It provides TUC waveforms for the ten most recent events of any appreciable magnitude or importance as well as a map showing the event location (epicenter) and the great circle path to TUC. The great circle path is the shortest distance between the epicenter and TUC. On a flat (2-dimensional) surface, the shortest distance between two points is a straight line. On a 2-dimensional representation of a sphere, or a map, the shortest path appears curved. All three components of ground motion are displayed: vertical motion, horizontal radial motion, and horizontal tangential motion. The wiggles recorded on the three components represent the ground motion at TUC as the result of the arrivals of different seismic phases. This ground motion is very small (measured in nanometers; 10**-9 meters), and thus is not felt by people. Seismic phases travel at different velocities, which is why they arrive at different times on the seismogram. To identify these phases, seismologists use a travel time curve.

DATEYEARMAGDEPTHBAZDISTLOCATIONE#
Feb 22
2003
5.2
3
294
5
 Southern California 0
Feb 19
2003
6.5
3
316
44
 Unimak Island Region 7
Jan 22
2003
5.5
10
154
15
 Off of the Coast of Jalisco, Mexico 3
Jan 22
2003
7.3
33
153
15
 Near the Coast of Michoacan Mexico 8
Jan 21
2003
6.3
33
131
26
 Near the Coast of Guatemala 5
Jan 20
2003
7.5
33
260
94
 Solomon Islands 9
Jan 16
2003
6.0
10
315
19
 Off the coast of Oregon 6
Jan 10
2003
5.0
62
145
18
 Guerrero, Mexico 1
Nov 3
2002
7.9
10
335
39
 Central Alaska 4
Nov 2
2002
7.5
33
319
137
 Northern Sumatera, Indonesia 2

Depth is measured in kilometers beneath the surface of the earth. Depth can be a difficult thing to determine. Thus, many times the depth is fixed, based on an educated guess, at either 10km or 33km when inverting for the epicenter (lat,lon). A "depth" of 33 or 10 km should be a guide as to actual depth. BAZ is the backazimuth from station TUC to the source (earthquake) measured in degrees clockwise from north. DIST is distance in degrees along the great circle path. The great circle path is the shortest distance between two points on the surface of a sphere (one degree = 111km = 69 miles = 60 nautical miles = 60 minutes).


E-mail SASO