06/04/2003 06:00 PM: Aftershocks continued
to rattle nerves in the East Bay today. Although nothing over
magnitude 5 has been recorded in the last 24 hours, the
probability of a damaging aftershock in the next week is still
quite high - over 40%. UC Berkeley and USGS scientists are
studying the impact of this earthquake on the neighboring
Rodgers Creek fault. A number of recent studies have shown
that
large earthquakes increase the stress on some faults and
lower it on others, depending on the orientation of the faults.
Increasing the stress on a fault can move it closer to failure.
06/03/2003 06:00 PM: Many aftershocks of the
M6.5 have been recorded in the last day and a half, including an
M5.0 event this morning. Bay Area residents are likely to
experience more aftershocks in the coming days.
06/02/2003 02:00 AM: A few hours ago, a
magnitude 6.5 (Mw) earthquake struck along the northern
Hayward fault.
This is the largest earthquake in the San Francisco Bay Area since the
1989 Loma Prieta quake (Mw 6.9)
and the first to rupture the northern Hayward fault since
the mid 1700s.
The earthquake initiated 4 km ESE of Berkeley and
ruptured toward the north, with a strike-slip
mechanism. Approximately 35 km of the fault
are estimated to have ruptured, with an
average of 0.5 m of slip. This is large enough to
have ruptured some fault-crossing facilities.
At this point in time, we anticipate that this event
will be followed by numerous aftershocks. The probability
of a strong and possibly damaging aftershock in the next
7 days is greater than 90%.