Sunday, March 29, 2009
Anyway, got me to thinking if there could be a connection between a power plant accident and equivalent Richter magnitudes. I want to assure you, in the hour I allow myself to research and produce a blog, this did not eave much time for really thinking this idea through carefully. But I did find an equivalent Richter magnitude for the Chernobyl accident (not TMI) at Wikipedia (ok, not your most authoritative source). Then I made the below graph of equivalent Richter magnitudes. That's all (I've even kept the default Excel graph settings, utterly devoid of good design sense they may be).
Tuesday, March 24, 2009
Mt. Redoubt has been spewing ash, and the AVO has reports, tweets, photos, videos. But of course, here, we need to focus on seismograms of those harmonic tremors that accompany themagma moving in the volcano.
The webicorder at Redoubt is pretty intense right now. Have a look. The image at the time of this blog entry is shown below. Click on it for an enlarged image.
Sunday, March 22, 2009
The CGMW, the oldest international organization in geoscience after the International Geological Congress (IGC), was created in 1881 during the 2nd IGC in Bologna. It is a non-profit-making scientific and educational body governed by French law.
The CGMW is responsible for designing, promoting, coordinating, preparing and publishing small-scale thematic (geology, geophysics, ore deposits, natural resources, climate, etc.) Earth Science maps of continents, major regions, and oceans. In the context of its mission, the CGMW intends to play a leading role in the use and diffusion of digital cartographic techniques, as well as in the development of international standards.
The CGMW is affiliated to the International Union of Geological Sciences (IUGS) since the latter's creation in 1961 and cooperates closely with the International Union of Geodesy and Geophysics (IUGG) in the framework of ICSU geounions. Recognized as a rank A Non-Governmental Organization (NGO), the Commission is eligible for UNESCO funding, part of which is devoted to the co-publication of maps.
Geological Surveys (or similar organizations responsible for national geological mapping) of countries and territories throughout the World are Statutory Members of the CGMW. Other interested organizations can join the CGMW as Associate Members.
A score of key figures from different Earth Science fields make up the ad hoc Members of the Bureau in charge of running the CGMW, whose headquarters are in Paris.
General Assemblies are held every two years, alternately at the UNESCO headquarters in Paris, and at the venue of the International Geological Congress. A focal point of these meetings is to assess the aims of future programmes and the progress of current cartographic projects. The list of CGMW programmes for the period 2008-2012 is available here.
Thursday, March 19, 2009
Here is the basic information from the USGS:
|Depth||10 km (6.2 miles) set by location program|
|Distances||210 km (130 miles) SSE of NUKU'ALOFA, Tonga|
480 km (300 miles) ESE of Ndoi Island, Fiji
490 km (305 miles) S of Neiafu, Tonga
1830 km (1140 miles) NE of Auckland, New Zealand
Below is the seismogram from Franklin and Marshall College, broadband vertical component.
And let's continue our mini-tour of different geological surveys. Records of this event on seismographs across New Zealand are shown on the web pages of the Institute of Geological and Nuclear Sciences. Look at those waves sweep across the stations, as distance from the epicenter increases.
Pacific Tsunami Warning Center:
TSUNAMI MESSAGE NUMBER 3
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
1009 AM HST THU MAR 19 2009
TO - CIVIL DEFENSE IN THE STATE OF HAWAII
SUBJECT - FINAL TSUNAMI ADVISORY
THE TSUNAMI ADVISORY IS ENDED FOR THE STATE OF HAWAII EFFECTIVE
AT 1009 AM HST.
AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS
ORIGIN TIME - 0818 AM HST 19 MAR 2009
COORDINATES - 23.0 SOUTH 174.8 WEST
LOCATION - TONGA ISLANDS REGION
MAGNITUDE - 7.7 MOMENT
MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY
GAUGE LOCATION LAT LON TIME AMPL PER
------------------- ----- ------ ----- --------------- -----
NIUE 19.1S 169.9W 1911Z 0.04M / 0.1FT 06MIN
LAT - LATITUDE (N-NORTH, S-SOUTH)
LON - LONGITUDE (E-EAST, W-WEST)
TIME - TIME OF THE MEASUREMENT (Z IS UTC IS GREENWICH TIME)
AMPL - TSUNAMI AMPLITUDE MEASURED RELATIVE TO NORMAL SEA LEVEL.
IT IS ...NOT... CREST-TO-TROUGH WAVE HEIGHT.
VALUES ARE GIVEN IN BOTH METERS(M) AND FEET(FT).
PER - PERIOD OF TIME IN MINUTES(MIN) FROM ONE WAVE TO THE NEXT.
THE PACIFIC TSUNAMI WARNING CENTER HAS CANCELLED THE REGIONAL
TSUNAMI WARNING IT ISSUED FOR ANOTHER PART OF THE PACIFIC. BASED
ON ALL AVAILABLE DATA THERE IS NO DESTRUCTIVE TSUNAMI THREAT TO
HAWAII AND THE ADVISORY FOR HAWAII IS ALSO CANCELLED.
HOWEVER... SOME COASTAL AREAS IN HAWAII COULD EXPERIENCE SMALL
NON-DESTRUCTIVE SEA LEVEL CHANGES AND STRONG OR UNUSUAL CURRENTS
LASTING UP TO SEVERAL HOURS. THE ESTIMATED TIME SUCH EFFECTS
MIGHT BEGIN IS
0236 PM HST THU 19 MAR 2009
Wednesday, March 18, 2009
I won't claim to be an expert, but a Google search (shhh, don't tell my students) came up with a very nice PowerPoint from Dr. Brian Baptie of the Earthquake Seismology team, Earth Hazards and Systems Programme, British Geological Survey (excellent web site). The paper is on Seismo-tectonics and state of stress of the British Isles, presented at the 8th International Symposium on Upper Rhine Graben Evolution and Neotectonics. You can find and download the presentation here.
Baptie does indeed note a strong variation in spatial distribution of seismicity throughout the United Kingdom. Earthquakes occur in a north-south band along the length of Britain. But there is an absence of seismicity in northeast Britain, the northwest Atlantic margin and Ireland (as we pointed out yesterday). The rather striking pattern is shown in the figure below.
The figure above (click on it for an enlarged version) shows historical seismicity of the UK (yellow) from 1832 to 1970 for earthquakes of magnitude above 3.0 and instrumental seismicity (red) from 1970 to present for earthquakes with magnitudes > 2.0 (from Earthquakes in the UK).
Baptie concludes that a prevailing stress field due to northwest compression is dominant, suggesting a combination of plate boundary forces plus post-glacial rebound may be controlling re-activation of old faults.
Tuesday, March 17, 2009
"The largest recorded earthquake to have occurred in Ireland was a magnitude 2.3ML in Co. Leitrim in November 1994. There were no felt reports for this event.
"The largest recorded earthquake we have had offshore Ireland was a magnitude 5.4ML near the Welsh coast on 19 July 1984. This was felt mainly in Wales and adjacent parts of Britain, and over a significant area of the east coast of Ireland. There was some structural damage reported from North Wales adjacent to the epicentre of the event. More significant damage would have resulted had the event occurred at less than the estimated 20km depth."
Sounds pretty safe, earthquake-wise!
Happy St. Patrick's Day!
You can see a video clip of the exhibit. A recent book about Pompeii by Mary Beard, Cambridge classicist, has been very positively reviewed.
Anyway, a singer-songwriter whom I really admire is Michelle Shocked. I'm not kidding about her name - I didn't just make it up for the blog. I almost posted her video-song Anchorage (I love skateboard punk rockers) a couple of weeks ago when that city was somewhat threatened by Redoubt Volcano. And I love her song Come a Long Way. She has a new album coming out in May, and a song called Pompeii. Here's the video (by the way, any political views explicitly or implicitly expressed in this blog do not represent the opinions of anyone other than me):
Monday, March 9, 2009
SSA’s 2009 Annual Meeting will provide a stimulating exchange of research on a wide range of topics with like-minded professionals from all over the world. Oral presentations, poster sessions, exhibits, field trips, business meetings and social gatherings all provide members the opportunity to meet and share with their peers.
| || |
|Call for Special Sessions||1 October 2008|
|Travel Grant Deadline||30 November 2008|
|Abstract Submission Deadline||11 January 2009|
|Program w/ Abstracts Online||19 February 2009|
|Meeting Pre-registration Deadline||6 March 2009|
|Hotel Reservation Cut-Off||22 March 2009|
|Online Registration Cut-Off||27 March 2009|
The program includes 287 oral presentations, 200 posters, and the Joyner Lecture over a 3-day schedule. Downloadable PDF files of the program overview and schedule and a searchable online database of abstracts are available on the Program page.
Two field trips will be offered on Saturday, April 11, following the conference.
You may register for the meeting online. Registrations received prior to March 6, 2009 receive a 15% discount. Online registrations will be accepted through March 27. We do accept walk-in registrations as space allows.
Saturday, March 7, 2009
When we kept paper seismograms on a drum recorder before we went digital, we would mark the sheets with coordinated universal time (CUT) when we started and stopped the record, but we used the local date. That got to be too much when my assistants occasionally changed the paper later in the evening.
Anyway, my son was confused a few weeks ago because he thought he felt an earthquake in the Bay Area. He later found the SF Examiner reporting a regional quake at about that time. But the newspaper had mistakenly taken the reported earthquake time, in coordinated universal time, and mistaken it for local Pacific Coast time. So, the son was confused, but I straightened him out.
Most earthquake times are reported as CUT, which is essentially the same as Greenwich Mean Time, so that all seismologists will be talking about the same time when comparing data. Local media sources might report the quakes in local time. So watch out. Today, CUT is 5 hours ahead of Eastern Standard Time, but tomorrow CUT will be 4 hours ahead of Eastern Daylight Savings Time.
My source for things time is the U.S. Naval Observatory. We can read there that
Starting in 2007, daylight time begins in the United States on the second Sunday in March and ends on the first Sunday in November. On the second Sunday in March, clocks are set ahead one hour at 2:00 a.m. local standard time, which becomes 3:00 a.m. local daylight time. On the first Sunday in November, clocks are set back one hour at 2:00 a.m. local daylight time, which becomes 1:00 a.m. local standard time. These dates were established by Congress in the Energy Policy Act of 2005, Pub. L. no. 109-58, 119 Stat 594 (2005).Yep, the dates were revised to save energy. How about driving smaller cars, everyone?
There's a nice WebExhibit on DST here.
And to get the CUT right now, click here.
So how about a little tune to make us smile while we "spring ahead" tonight and lose an hour of sleep. I heard this group during my freshman year when they were called Chicago Transit Authority. Ouch! Nice brass, guys.
Friday, March 6, 2009
3/05/2009 03:40:00 PM
Now, when you search for "earthquakes" on Google, you'll get information on some of the most recent, significant earthquakes from around the world, right on the search results page. From there, you can click through to the USGS Earthquake Center for more information, or visit the epicenter of any quake on Google Maps. To find earthquakes closer to home, you can add a location to your query, for example: "earthquakes California."
Earthquake search is the latest of Google's special search features, and many others can help you in different ways. If you'd like to know the local time where an earthquake occurred, search for "time" followed by the location (for example, "time Japan"). Let's say the epicenter was 50km from the coast and you want to know how far that is in miles. Type "50km in miles" into the search box. You can find out about these special features and many more on the Search Features page.
Wednesday, March 4, 2009
One list is at the German site geoberg.de.
I discovered a relevant blog there today, the Berkeley Seismo blog. Looks pretty good, don't know how I missed it up til now. But since our blog here is northeastern U.S.-centric, I think we can co-exist.
I've kept my own blogroll on the left minimal, to include blogs more related to earthquakes and seismology, that are regularly posted to, and professionally oriented. Am I missing any of your favorites?
But I'm not yet ready to start twittering. I'm with Gary Trudeau/Doonesbury on this one, so far.
Sunday, March 1, 2009
Personally, I found Bobby Jindal's Republican response to President Obama's speech last week to be bankrupt of new ideas, but at least the presentation style was totally wooden and robotic.
But what about his comment on volcano monitoring? As you can read more about at Scientific American, Gov. Jindal blasted elements of the economic stimulus package as “wasteful spending”– among them, “$140 million for something called volcano monitoring” at the USGS.
“Instead of monitoring volcanoes, what Congress should be monitoring is the eruption of spending in Washington, D.C.,” Jindal said.
Congress authorized some of that $140 million to be spent on volcano monitoring, but not all of it. That line, ProPublica says, is directed to “U.S. Geological Survey facilities and equipment, including stream gages, seismic and volcano monitoring systems and national map activities.” Next thing you know, federal earthquake monitoring will be attacked.
Then we will all be New York state.