That 4.0 in Yorba Linda sure qualifies for this one - or it matches another pair of quakes that we had last night/this morning:
00/03/05 09:07:55 14.35N 92.74W 33.0 4.6Mb B NEAR COAST OF CHIAPAS, MEXICO
00/03/05 10:50:38 28.08N 111.69W 10.0 4.0Ml B GULF OF CALIFORNIA

I only think one of these will be the 'final solution':
4.0 2000/03/06 16:20:28 33.806N 117.715W 11.3 12 km ( 8 mi) NE of Tustin, CA
4.0 2000/03/06 16:20:28 33.813N 117.713W 10.0 12 km ( 7 mi) ESE of Yorba Linda, CA

So we either have another one coming or the quake today was it... Sorry I'm no help on this one!

Canie