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Monday, September 20th, 2004
Update at 8:00 AM (PDT) on Monday, September 20, 2004:
Earthquake activity within and adjacent to Long Valley caldera remains
low with only one small (M<2)
earthquake detected and located by the realtime computer system in the last
24 hours.
Elsewhere, the earthquake swarm beneath the Adobe Hill 18 miles east of
Mono Lake continues. As of this
update, it has included over 300 earthquakes since it began just after midnight
on Sept. 18. Twenty three
of these have had magnitudes of M=3.0 or greater and five have had magnitudes
of M=4.0 or greater.
The two largest earthquakes were M=5.5 and M=5.4 earthquakes at 4:02PM and
4:43 PM on the 18th.
The most recent M=3.0 earthquake occurred at 4:19 AM this morning (the 20th).
This update is from USGS
Long Valley Observatory
The magnitude-5.5 temblor that struck at 4:02 p.m. Saturday, was followed
by a magnitude-5.4 quake at 4:43 p.m. The moderate quakes were the biggest
in the swarm and the biggest on the fault in more than a decade.
There were no immediate reports of any injuries or damage from the temblors
centered along the
California-Nevada line about 30 miles northeast of Mammoth Lakes.
May 15th 1999 - Here we go again.....
A magnitude 5.6 earthquake occured at 6.22 AM local time on May 15th 1999.
Epicenter was 8 miles WSW of Toms Place - 12 miles southeast of Mammoth Lakes.
The earthquake has been followed by quite a number of aftershocks, in fact
as many as 760 during
the next 24 hours, of which at least 20 had a magnitude of 3.0 or greater,
and four of 4.0 or greater.
| Date | Local time | Mag |
| May 16th May 15th |
05:31 05:18 04:30 20:57 20:28 16:34 14:40 13:11 12:15 10:54 08:59 07:36 07:36 07:36 07:28 07:01 06:59 06:38 06:38 06:28 06:22 |
3.2 |
Compare this table to the previous ones further down this page, having only
3-5 larger quakes per day.
However, USGS says that aftershocks can still be expected, up to 4 or 5, but
the activity in the Long
Valley Caldera has not shown any increase in activity, so condition remains
GREEN.
According to a CNN report there has been no damage or injuries.
But if it had occured in an urban area, it could have caused quite a bit of
damage. If there is ever
a good place for an earthquake to occur, this is a good place, said a spokesman
for USGS i Menlo Park, California. The quake was however, the largest in 3
years..
Latest: Jan.21st 1998: December 14th, 1997 to Jan.5th 1998: According to reports from USGS (U.S.Geological Survey) this area has produced
numerous volcanic eruptions over the last 3 million years, including a massive
eruption 760.000 years ago. The most recent eruptions occured just 500 to 600
years ago along the Mono Crater-Inyo crater volcanic chain, which extends south
from Mono Lake into the western part of Long
Valley caldera.
During May 1980 a swarm of earthquakes hit the area, 4 of these had a magnitude
6, and that marked the onset of a period of unrest that continues up to now. However, as eruptions occurs every 250 to 750 years, the last big one was
about 500 years ago, so why not now? Not that I want it, but IF it is coming,
it's one of those nature wonders only happening once in a lifetime, and I don't
want to read in the papers weeks later that I missed it. etc
Now, lets go back to Lake Mammoth again. This nice little community way up
in the mountains, how do they feel about it? Quoting their electronic newspaper
Mammoth Times Online:
Seismicity in the caldera declined to its lowest level in nearly two months, since
the resurgence of activity along the south side of the caldera began on November
22. During the past week only 18 earthquakes occurred in the caldera that were
as large as M2.0. Only two of these were as large as M3. This compares to the
previous week when 75 M>2 earthquakes occurred, nine of which were as large as
M3. (Copy from USGS)
After three weeks of heavy activity, it seemed like it has calmed down. Week
ending Dec.14th only had some 400 quakes over 1.5, and total quakes per day
has fallen quickly. But then on Dec. 29th after a M 4.3 shock, it started all
over again:
last time this time
total quakes magnitude total quakes magnitude
------------ --------- ------------- ---------
Nov.30: - M 4.9 Dec. 29: 562 M 4.3, 3.0
Dec. 1: 1805 Dec. 30: 756
2: 1867 M 3.7, M 3.2 Dec. 31: 785 M 4.8, 3.6, 3.7,
3: 1918 M 3.8, M 3.0 3.3, 3,5, 3,5
4: 1941 M 4.0 Jan. 01: 1639 M 3.1, 3.8
5: 1965** M 3.2 Jan. 02: 1854 M 3.1
6: 1935 M 3.0 Jan. 03: 2017 M 3.0, 3.0, 3.2
7: 1887 M 3.0 3.6, 3.4
8: 1260 Jan. 04: 2140 M 3.2, 3.6
9: 1173 M 3.7 Jan. 05: 2302 M 4.1
10: 1009 M 3.0 Jan. 06: 2363 M 3.1
11: 1011 M 3.7 Jan. 07: 2419
12: 948 Jan. 08: 1976
13: 870 Jan. 09: 1549 M 3.4, 3.6, 3.8
Jan. 10: 1458 M 3.0
Jan. 11: 1319 M 3.7, 3.2, 3.2
Jan. 12: 1220
Jan. 23: 255 quiet.
Mammoth Lake has really been put on the map,
as swarms of earthquakes have hit the area for the past three weeks. Mammoth Lake
is a beatiful summer/winter resort lying high up in the Sierra Mountains, just
a few miles south of the famous Yosemite
National Park. As they say, you have to see it to believe it. Several links
to the places further down the page...
As illustrated in the ... some 20 small to moderate eruptions have occured along
the Inyo-Mono Craters in the last 5.000 years. Does the new activity means that
we can expect another eruption now? According to USGS the possibility is compareable
with odds for a great (magnitude 8) earthquake occuring on the coast of California,
and odds are smaller than for a major (magnitde 7 or greater) earthquake in
L.A. or S.F. area.
"Where else can one experience the thrill of an earthquake on earth without
getting hurt? I think we have a new tourist attraction....We check out USGS
website all day as we try to guess the magnitudes of each quake...". They say
that they can feel any quake above 2.5 there, and sometimes they get several
during only one day. On November 25th they had one at 3.0, one more the following
day, and on the 30th of November a bigger one at 4,8, followed by 4 around 3,0-3,1.
Would like to keep myself informed. And it's interesting to see what is going
to happen. I still remember SURTSEY off
the coast of Iceland several years ago. So, if you think there is going to happen
something more here, stay with me for a while...
I don't really understand much of what all those Volcanic-stations reports,
but one thing is for sure - there is a lot of
eruptions around. Anyone else interested in following,
please get in touch!
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