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Seismology: Earthquakes - The Science and Updates on Current Activity

topic 9 · 160 responses
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~MarciaH Sat, Jul 10, 1999 (23:39) seed
Earthquakes are monitored world wide. When the earth moves under you feet and you do not know why, look here for your local update.
~wolf Sun, Jul 11, 1999 (17:31) #1
Is there a site where we can find current faultlines?
~MarciaH Sun, Jul 11, 1999 (19:03) #2
The quick answer is there is no good one that I know of but have sent the request to my family expert. Usually they appear as a line of earthquakes as in http://www.geophys.washington.edu/CNSS/us.epi.gif I will search it further. At this URL you will find links to your area which is about as stable as it is possible to get. Water is your enemy, not the earth beneath it! http://quake.wr.usgs.gov/QUAKES/CURRENT/current.html
~MarciaH Sun, Jul 11, 1999 (19:15) #3
For my current seismic activity for my location Check out the zoomable map at the bottom of the page. http://quake.wr.usgs.gov/cgi-bin/quake/tako.wr.usgs.gov/db=usa/river=1/fed.=1 YY MM DD HH MM SS Lat Long Depth Mag Q Point of Reference || || || || || || ||.|| |||.|| ||.| |.| | 99/07/08 02:55:54 19.32N 155.09W 5.1 2.6MGN B* 5 mi. S of Puu O'O 99/07/08 03:04:16 19.33N 155.09W 2.3 2.6MGN B* 4 mi. S of Puu O'O 99/07/08 07:49:36 19.19N 155.45W 18.3 2.0MGN C* 2 mi. ESE of Pahala 99/07/08 16:38:48 19.73N 155.80W 0.9 2.4MLG B* 15 mi. ENE of Kailua-Kona 99/07/10 09:27:57 19.34N 155.13W 0.3 2.3MGN A* 4 mi. SSW of Puu O'O 99/07/10 12:53:58 19.33N 155.12W 3.3 2.2MGN C* 4 mi. SSW of Puu O'O 99/07/10 13:09:45 19.70N 155.82W 31.3 2.2MLG B* 13 mi. ENE of Kailua-Kona 99/07/10 15:52:23 19.36N 155.08W 1.4 2.3MGN B* 2 mi. SE of Puu O'O 99/07/10 22:44:05 19.49N 155.35W 14.7 2.0MGN A* 18 mi. WNW of Puu O'O 99/07/10 23:09:06 19.35N 155.07W 1.8 2.5MGN B* 3 mi. SE of Puu O'O ---------------------------------------------- <> Last update was on 10-JUL-1999 23:11 HST ------------------------------------------------
~MarciaH Sun, Jul 11, 1999 (21:48) #4
David has come through for me and here are his suggestions for fault maps: There are several related sources. You may like the ABAG site with forecast damage estimate maps: http://www.abag.ca.gov/bayarea/eqmaps/eqmaps.html and http://www.geophys.washington.edu/seismosurfing.html The best simple fault map is on the CA quake pages at: http://quake.wr.usgs.gov/recenteqs/ Be sure to check the Bay Area version cause it has lots of what folks will want to see.
~livamago Tue, Jul 13, 1999 (22:08) #5
Marcia, there was some seismic activity in Central America this weekend. Can you find the particulars? I had conflicting reports.
~MarciaH Tue, Jul 13, 1999 (23:21) #6
There were two Earthquakes in Honduras: 99/07/11 20:09:21 15.71N 88.51W 10.0 4.4Mb B HONDURAS 99/07/11 20:17:25 15.29N 88.38W 10.0 4.3Mb B HONDURAS Maps and more information is available at http://quake.wr.usgs.gov/cgi-bin/quake/
~MarciaH Tue, Jul 13, 1999 (23:21) #7
There were two Earthquakes in Honduras: 99/07/11 20:09:21 15.71N 88.51W 10.0 4.4Mb B HONDURAS 99/07/11 20:17:25 15.29N 88.38W 10.0 4.3Mb B HONDURAS Maps and more information is available at http://quake.wr.usgs.gov/cgi-bin/quake/
~patas Tue, Jul 27, 1999 (08:35) #8
Lisbon is in a seysmic zone, and after the "big one" in 1755 that was followed by a tidal wave and fires that dertroyed most of the city, we have never felt quite safe again. There was a reasonably strong earthquake in 1968 (I'm writing from memory and haven't checked the particulars so cannot give you any numbers)but people say it "wasn't it", they still fear a bigger one! I was very young and living in Madeira in 68, but woke up in the night and felt the quake.
~wolf Tue, Jul 27, 1999 (09:59) #9
when my father was stationed in san francisco, we had an earth tremor. just a baby at the time, so i remember nothing about it.
~MarciaH Tue, Jul 27, 1999 (13:02) #10
You need to move to a more active place than you are now...You have just about no chance of feeling a really fun Earth quake in La Belle Lousiana
~wolf Tue, Jul 27, 1999 (17:31) #11
no thanks, that's one experience i think i'll pass on (i mean, no guarantees, right?)
~MarciaH Tue, Jul 27, 1999 (18:32) #12
The only guarantee is No Guarantees!
~KitchenManager Tue, Jul 27, 1999 (20:09) #13
kind of like posting on the Spring...
~wolf Tue, Jul 27, 1999 (20:13) #14
so true, we're lucky to stay on topic!!
~KitchenManager Tue, Jul 27, 1999 (20:49) #15
we're lucky if we can still keep it in sight while we're straying away!
~MarciaH Tue, Jul 27, 1999 (20:56) #16
That's odd. I thought we were posting on the Spring (as I drag my seismograph and stand along behind me...)
~KitchenManager Tue, Jul 27, 1999 (22:50) #17
any conclusions yet?
~KarenR Wed, Jul 28, 1999 (00:18) #18
You have just about no chance of feeling a really fun Earth quake in La Belle Lousiana Now hold your beignets! They could probably feel something from that New Madras fault. A long, long time ago, when I was visiting older sis in college down at U ofI, I got woken up by earth tremors coming from that region. Chicago can get them, so they probably head south as well.
~KarenR Wed, Jul 28, 1999 (00:23) #19
...unless it's too soggy down there
~MarciaH Wed, Jul 28, 1999 (10:55) #20
(Karen)...unless it's too soggy down there That's my guess. It mostly depends on your substrate. If you are on the same plate and the same portion of the bedrock, you will be able to feel a strong one from quite far away. It is on this principle that seismographs work. The ones at the epicenter are knocked off-line almost instantaneously with a local earthquake, so the magnitude and epicenter have to be extrapolated from the data obtained from the network of Seismic stations around the world. At the Hawaii Volcanoes Observatory, where ours are located, the Good Friday quake in Alaska some years ago made a very impressive readout. I think it is still on display. However, that said, the New Madrid Fault quakes have changed the course of the Mississippi, so it just might have been felt in Lousiana, despite the dampening effect of the bog on which it sits.
~KarenR Wed, Jul 28, 1999 (12:25) #21
New Madrid, well, I knew it started with an M!! Strange though that I did a search on Yahoo! and an article there talked about the New Madras Fault as well. According to these two site, the fault cuts across 5 states, but none mentioned affecting Louisiana, excepting as you said Marcia the course of the Mississippi!! http://www.ceri.memphis.edu/www/public_info/faultfacts.html http://quake.ualr.edu/public/nmfz.htm
~MarciaH Wed, Jul 28, 1999 (15:48) #22
Oh Karen..thanks for the links. For those not knowing, Madrid in Spain is not the way they pronounce it for the New Madrid Fault. This case is pronounced MAA-drid (accent on the first syllable.)
~KarenR Wed, Jul 28, 1999 (16:22) #23
I was going to mention the difference in pronunciation (as all foreign place names in the Midwest), but didn't think Geo was the place. ;-D Although, I would add another D in there. MAAD-drid. My fav is upriver in Cairo, Il. You know how that's pronounced? BTW, we're relevant here as Cairo is along the fault line.
~KarenR Wed, Jul 28, 1999 (16:24) #24
Wolf could add the La. versions of French words, like the street names in Nawlins.
~MarciaH Wed, Jul 28, 1999 (19:40) #25
KAY row we all have our regional peculiarities. In Maine Calais is pronounced Callous (like on the bottom of your foot!)
~patas Thu, Jul 29, 1999 (03:16) #26
WoW! I like to learn these things to. To talk of such places with the right pronunciation makes one sound *very* cool! (Like one has been there) ;-)
~MarciaH Thu, Jul 29, 1999 (11:47) #27
(Fun, is it not!!) In Pennsylvania they are very capricious with their French place-names. Charleroi (Charles-le-Roi) is pronounced the French way (excepting the roi part which is pronounced roy), but DuBois is DOO bose. Amazing!
~KarenR Thu, Jul 29, 1999 (14:01) #28
In Wisconsin (or is it Michigan or maybe it's Illi-NWA), there is a Charlesvoix, pronounced: SHAR-le-voy. A little bit of both.
~KarenR Thu, Jul 29, 1999 (14:08) #29
Another: in Illi-NWA, we have a lot of French place names because of Joliet and Champlain--one of them was a Pere, forget which). South of Chicago, is Bourbonnais. Have heard it pronounced: Bur-BON-is and Bur-bon-aze.
~KarenR Thu, Jul 29, 1999 (14:10) #30
and Marseilles, which is of course: Mar-SAILS
~wolf Thu, Jul 29, 1999 (17:51) #31
well, and then there's nacogdotches and nacodetches (or something like that). in LA, it's nack-ah-dish and in texas, it's nack-ah-doe-chez. i think they're even spelled the same way!
~MarciaH Thu, Jul 29, 1999 (18:37) #32
Ok, people, admit it. When you wear the cloth of kings (whether wide wale or narrow) you call it Cor-doo-roy or Cor-der-roy ...not Cord-Du-Roi
~wolf Thu, Jul 29, 1999 (18:42) #33
i call it yucky! *smile*
~KarenR Thu, Jul 29, 1999 (19:25) #34
oops, and it was Pere Marquette in that little canoe... you call it Cor-doo-roy or Cor-der-roy ...not Cord-Du-Roi depends on if it's been good or bad and if it's going to get any supper that night! ;-p
~MarciaH Fri, Jul 30, 1999 (00:03) #35
*lol* how do you think up these comments! Especially after a ziooion hours a day doing this - like me - but I am almost brain-dead at this point.
~KarenR Sun, Aug 8, 1999 (17:59) #36
Being brain-dead is a requirement. ;-p
~MarciaH Sun, Aug 8, 1999 (18:45) #37
You know, I wondered about those electrodes they afixed to my scalp before turning this Conference over to my care. No business going on in here - I think I'll go up to the observatory and jump up and down on their seiso-cables. You see tourist and little kids doing that all the time. Very funny! And quite undetectable.
~MarciaH Fri, Aug 13, 1999 (14:14) #38
Here is an excellent source of information for teachers (which also means parents) This particular issue is about Natural Disasters and overcoming science myths (that is what they said!) http://www.earthsky.com/Teachers/Booklet/natural_disasters.html
~KitchenManager Fri, Aug 13, 1999 (23:34) #39
I wonder if ratthing heard that...and what he'd have to say on the topic of "science myths"...?
~MarciaH Fri, Aug 13, 1999 (23:41) #40
I wondered about that, too. I was busy today so I did not check out the URL as thoroughly as I usually do...shall report tomorrow...stayed tuned!
~MarciaH Mon, Aug 16, 1999 (19:49) #41
We have just experienced a 4.5 Earthquake. I thought a hurricane would be about all I needed to make my day complete...until now!
~KarenR Tue, Aug 17, 1999 (18:12) #42
Nothing on the 7.1 earthquake in Turkey? Get out of the Bath, Marcia! ;-o
~MarciaH Tue, Aug 17, 1999 (20:42) #43
I was waiting to see if anyone else was aware of it while I waited for Cal Tech to update their stuff and give me something more substantial to post. Willl check in again and post what I can find.
~wolf Tue, Aug 17, 1999 (21:15) #44
msn on line is reporting 1000 dead but the news says 2000 and thousands missing. they're having aftershocks and fear an even bigger quake during the night. let's pray not.
~MarciaH Tue, Aug 17, 1999 (21:31) #45
Since the Earthquake resources are still not reporting anything, I went to The Times of London for information: http://www.sunday-times.co.uk:80/news/pages/Times/frontpage.html?1319194 bul toll rises to more than 2,000 � A young girl is carried out of the wreckage of her demolished home in Istanbul after the quake yesterday Photograph: AP Turks call for earthquake aid BY ANDREW FINKEL IN IZMIT TURKEY was counting its dead yesterday after a major earthquake devastated western parts of the country. More than 2,000 people are believed to have been killed over a wide area from the extreme western Istanbul suburb of Halkali to Asia and the industrial city of Izmit about 60 miles to the east. At least 11,000 are thought to have been injured. Survivors tore at mangled steel and concrete to free loved ones, and officials asked the international community to send sniffer dogs and lifting equipment to help in the rescue. The whole region shook for 45 seconds at 3.02 am local time (1.02 BST) yesterday, driving millions of people from their beds out into the street. Turkish seismologists calculated the initial tremor at 6.7 on the Richter scale. But the British Geological Survey, Harvard University and other centres around the world later calculated the magnitude as at least 7.5. The tremor was felt with violent intensity in the capital Ankara, some 270 miles from the epicentre in a fault segment running from Izmit to Lake Sapanca. Bulent Ecevit, the Turkish Prime Minister, appeared close to tears during a visit to devastated towns. "The loss is huge," he said in a trembling voice."It is the biggest natural disaster I have witnessed. May Allah help our state and our people." Most of the those who died were killed as they slept when substandard buildings collapsed. The Istanbul neighbourhood of Avcilar, far from the epicentre, was badly hit. The stricken region also includes Yalova, Bursa, Adapazari, Bolu and Eskisehir - an area which defines the industrial and commercial heartland of Turkey and to emphasise the point smoke billowed from the country's main oil refinery at Izmet. The naval base at Golcuk across Izmit Bay was also badly hit. A handover of command ceremony had taken place on Monday and many high-ranking officers had decided to stay overnight. Twenty bodies were recovered and more than 200 were missing feared dead. While most of the structural damage was to blocks of flats, the early 16th-century Beyazid Mosque in Istanbul was one of the few historical buildings to suffer substantial damage. Along the highway approach to Izmit, some apartment blocks looked as if someone had taken an axe to split them in two, and the force of the quake turned one five-storey block in the town of Korfez on to its side. Other buildings simply collapsed one floor on top of the other with mattresses and carpets sticking out at the end to define the layers. The minaret on the town's mosque lay draped over the building like a limp sock. Many of those trapped under the rubble were taken to Izmit state hospital, which presented a scene reminiscent of the Inferno. A car park littered with bandages and surgical gloves was converted into an emergency ward with relatives holding up pieces of cardboard to shade loved ones as their wounds were being stitched. Inside, three of the four operating theatres were in constant use, even although there was no city water and the emergency electrical generator was not working. The corridors of the hospital were filled with the injured, while those not in a critical condition were taken to the park across the street. "I don't know if I should be thinking of myself or my family," said a dazed 20-year-old sitting outside, a saline drip suspended from a railing and his face still caked in blood. He was one of the lucky ones who had been rescued within the first hour and brought in to have his arm, broken in three places, mended. He had no knowledge of the fate of his parents or younger brother, still missing in the rubble. Turkey has in the past been unwilling to accept international assistance after an earthquake, but Mr Ecevit, who was manning a special crisis centre, made clear that there would be no such reluctance this time. He urged international organisations to be patient as there might be logistical problems in getting aid to where it was needed most. He also urged Turks to refrain from using bulldozers to clear the wreckage, warning them that such powerful intervention might kill those trapped in air pockets. "Some of our citizens who lost their loved ones under wreckage demand heavy machinery to clear it and save their relatives. But if we do this we can lose more people than we save. So we have to be patient and wait," he said. Britain sent a team of 42 experts including firefighters and those trained in search-and-rescue operations, and other countries - including some that have been at odds with Turkey - promised help. Greece offered crews experienced in recovering survivors from ruined buildings. Bill Richardson, the US Energy Secretary, who was in Istanbul, consulted his Turkish counterpart about American assistance, and President Clinton said: "Turkey has been our friend and our ally for a long time now. We must stand with them and do whatever we can to help them get through this terrible crisis." Two Britons were among the wounded, neither of them with life-threatening injuries. A schoolboy who had been listed as missing was found safe. Next page: Andrew Finkel reflects on the tremor aftermath
~wolf Tue, Aug 17, 1999 (21:40) #46
i believe we're sending in search and rescue troops out of virginia. the best in the country (not military). i can only imagine what contracting must be like over there right now (i.e., the military bases etc.) and i have a friend who will be moving there with his family next week. :(
~MarciaH Tue, Aug 17, 1999 (21:44) #47
You don't want to know...Those search and rescue teams with the sniffer dogs are veterans of the Mexico City quake and numerous others. They are the best in the world at that unhappy task. We can all be grateful that they are willing to do it.
~wolf Tue, Aug 17, 1999 (21:50) #48
indeed, so!
~MarciaH Wed, Aug 18, 1999 (00:28) #49
My son reports that a rode out a 5.0 earthquake in central California MAG DATE LOCAL-TIME LAT LON DEPTH LOCATION y/m/d h:m:s deg deg km 5.0 99/08/17 18:06:18 37.91N 122.69W 6.9 0 mi SSW of BOLINAS More information is available at this URL: http://quake.wr.usgs.gov/recenteqs/Quakes/quakes.big.html
~wolf Wed, Aug 18, 1999 (10:31) #50
the numbers in turkey are over 3500 dead and still 10's of thousands missing. from what i understand, none of the us military bases were hit.
~MarciaH Wed, Aug 18, 1999 (12:56) #51
That is my understanding at this hour. Two sniffer-dog rescue units are there from the US...one from Virginia and one from Florida - to be joined by units from Japan and other countries, including Greece, its arch-enemy. In times like this, national disputes seem very petty, indeed!
~KarenR Wed, Aug 18, 1999 (14:29) #52
eh, eh, eh. Last night on the news, they said the largest contingent to come over was from Israel. Having been to Turkey fairly recently (less than 2 yrs ago) I think the US AF bases are northeast from this area, along the Black Sea--as close as they dared to the former Soviet Union. Am amazed that those historic buildings in Istanbul are still standing. 7.4 on the scale, they say.
~MarciaH Wed, Aug 18, 1999 (15:35) #53
http://wwwneic.cr.usgs.gov/neis/bulletin/990817000138.HTML 99/08/17 00:01:38 40.69N 29.82E 10.0 7.4Mw TURKEY The following is a release by the United States Geological Survey, National Earthquake Information Center: A major earthquake occurred about 55 miles (90 km) east-southeast of Istanbul or about 165 miles (270 km) west-northwest of Ankara at 6:02 PM MDT, Aug 16, 1999 (Aug 17 at 3:02 AM local time in Turkey). A PRELIMINARY MAGNITUDE OF 7.8 WAS COMPUTED FOR THIS EARTHQUAKE. The magnitude and location may change slightly as additional data are received from other seismograph stations. At least 2,000 people killed, 10,000 injured, many missing and extensive damage in the Istanbul-Adapazari area. Much of the damage and casualties occured in the provinces of Kocaeli and Sakarya. Felt as far east as Ankara. There is discussion that the California quake David felt was the compression wave travelling around the earth (see diagram in above url.) Turkey is on a plate boundary, and any movement on a plate boundary makes all of the other plates move. The San Andreas fault quake yesterday in California is the result.
~wolf Wed, Aug 18, 1999 (18:00) #54
amazing when you look at the mileage! turkey being so far away from california.
~MarciaH Wed, Aug 18, 1999 (18:41) #55
I guess this big blue marble is not all that big. I have heard Earthquakes described as striking a bell or a gong. It reverberates for a long while before all of the oscillations fade into the background.
~wolf Wed, Aug 18, 1999 (20:51) #56
i'm sure it does, just like ripples in the water...
~MarciaH Fri, Aug 20, 1999 (20:48) #57
Exactly analagous...
~patas Sun, Aug 22, 1999 (04:23) #58
Do you have anything on Lisbon's fault and seismic history, Marcia? Apart from the 1755 earthquake.
~MarciaH Sun, Aug 22, 1999 (12:13) #59
I shall look it up - I am sure data is available, and with luck a plot of mapping of the faulting. Gives me something to do besides wring my hands over this hurricane about to assault Texas. Thank you for asking.
~patas Sun, Aug 22, 1999 (12:44) #60
You won't believe this but I give you my word it's true. Earlier today there was a warning issued by the Maritime Authority that a giant ocean wave about 40 metres high was going to hit the Algarve (southern Portugal) coast. The beaches were evacuated, as were some restaurants and private homes. People gathered at high points to watch it appear. I didn't hear of it until about an hour ago, found it peculiar (but exciting, I admit) and asked my DH to call the "Civilian Protection Service" to find out more. Here's what we learned: the CPS had told the Maritime Authority to issue a warning that a heat wave of about 40�celsius would hit the Algarve this afternoon. Someone must have drunk a little to much at lunch and the warning came out as it did...
~MarciaH Sun, Aug 22, 1999 (12:48) #61
Too scary but funny! That is like the 40' lava wave that was going to sweep over Hilo as reported in mainland US newspapers. That is impossible. Lava moves pretty rapidly down slopes fresh from the vest, but not at 40' high and not sweeping...more like creeping. We did get a lot of phone calls, though. That is highly irresponsible reporting!!! Thanks for sharing, and stay cool!
~MarciaH Tue, Sep 7, 1999 (13:15) #62
The current information on the Greek Earthquake has not hit The Times of London yet, and am waiting for more information from Geological sources. Updates as soon as I can find them. 99/09/07 11:56:50 38.13N 23.55E 10.0 5.8Mb A GREECE
~MarciaH Tue, Sep 7, 1999 (16:10) #63
From the BBC: Tuesday, September 7, 1999 Published at 19:29 GMT 20:29 UK Earthquake rocks Athens An earthquake has shaken the Greek capital Athens, killing at least 20 people and leaving more than 100 trapped inside collapsed buildings. Three children are said to be among those who died in the tremor, which struck around 1500 local time (1200 GMT) and was followed by a series of strong aftershocks. Thousands of Athenians who were taking an afternoon siesta, fled into streets when the tremor occurred. People were hit by falling glass, concrete and marble slabs. At least three were killed when a building collapsed in the northern working-class surburb of Menidi. Emergency services are trying to free 70 people trapped under a collapsed detergent factory in the northern Tatoi suburb, one of the worst hit areas. A further 20 people were reported trapped in the ruins of a flattened apartment building. Reports say up to 100 buildings have been destroyed in the tremor. A government spokesman said many people were trapped inside buildings and several dozen had been transported to hospital. Cracks appeared in buildings in the historic Plaka district, but there was no apparent damage to ancient sites, including the Acropolis and the Temple of Zeus. The Athens Seismological Institute said the quake registered 5.9 on the Richter scale, and its epicentre was 20km (12.4 miles) north of the capital. Experts said the seismic shift occurred 5 to 10km below the ground.
~patas Thu, Sep 9, 1999 (07:31) #64
Is there a site where I can find a sort of map of the earth's seismic faults, Marcia?
~MarciaH Thu, Sep 9, 1999 (14:07) #65
Still looking for that map. There are several with local locations - like around San Francisco, or California in general. Will check for one for Lisbon for you (Portugal? Elsewhere?)
~patas Thu, Sep 9, 1999 (14:20) #66
Thanks! What I really want to know is the relationship between Lisbon's fault and others. If there is such a thing.
~MarciaH Fri, Sep 10, 1999 (22:17) #67
I will keep checking for the world-wide system, but All of the European coastline on the Atlantic is along the plate boundaries of the European Plate and the Atlantic Plate. By their very nature they grind and slide past one another as the earth fluctuates with celestial tugging by moon and sun. That is what caused the great quake in Turkey, recently.
~patas Sun, Sep 12, 1999 (03:59) #68
...And in Greece? And two years ago in Italy? why one place and not another? Shall we be next? Stupid questions, I know, but we are worried. I guess only the events in East Timor have taken our collective mind away from that worry.
~MarciaH Sun, Sep 12, 1999 (14:13) #69
I could answer your question better if I knew if they had strain meters along your part of the plate boundary, and whether or not there was evidence of strain building up in the rock beneath. I trust it is being monitored and you will hear far before it becomes life-or-death time. The problem with that is the panic factor. The powers that be in places like New York City, have said that fewer people would die from the earthquake they did not know was coming than from the panic ensuing trying to leave the city if they did know one was imminent. Terrible though it might seem, that may be the only viable option with the populations centered as they are. Alas, anything bordering the Mediterranean is a natural for earth upheavals. Your only sure bet would be to move to the less populated outskirts of the city, and away from the coast.
~MarciaH Sun, Sep 12, 1999 (14:23) #70
Ah, and your question, why in one place and not in another: Some places the rock is more fragile and fractures more easily...in others it is just a case of when one large piece of something past another, each with great inertia. It hops rather than slides along, resulting in a big quake at the point of the hop. Sometimes this is entirely arbitrary where it occurs, but others have had the way paved by smaller ones which tend to lubricate the slide and make that area more prone to quakes. It is an imprecise science at best.
~MarciaH Sun, Sep 12, 1999 (16:35) #71
There has been an EarthQuake swarm on Kilauea today so I am hoping to get up there to look around and see what is happening: From Quake Map:
~wolf Sun, Sep 12, 1999 (18:32) #72
that's a first for me, what's an earth quake swarm?
~MarciaH Sun, Sep 12, 1999 (20:03) #73
They occur when magma is moving down the rift zone (a network of cracks in the volcano's structure)under the surface. It usually precedes an eruption by a little while (hours to days), and the park service closes off access to the public for their protection. As soon as the eruption takes place and stabilizes itself in a specific area, they open it to the public for viewing. It is one of the most exciting things I can think of doing - anywhere, any time.
~patas Mon, Sep 13, 1999 (13:52) #74
Must be! Thank you, Marcia, for looking for my "fault information". There has been a new earthquake in Turkey this afternoon - have you heard?
~MarciaH Mon, Sep 13, 1999 (14:04) #75
I had not. Thanks for the update. I just posted information about the ongoing activity at Kilauea volcano on Geo 2. Will post updates on both sites as the day progresses.
~MarciaH Mon, Sep 20, 1999 (15:20) #76
A 7.6 EarthQuake has been reported in Taiwan. A tusnami Alert has been issued. More news as it becomes available.
~MarciaH Mon, Sep 20, 1999 (18:00) #77
From http://quake.wr.usgs.gov/cgi-bin/finger?quake@gldfs.cr.usgs.gov 99/09/20 17:47:19 23.78N 121.09E 33.0 7.6Ms A TAIWAN 99/09/20 17:57:16 23.80N 121.34E 33.0 6.0Mb B TAIWAN 99/09/20 18:03:44 23.65N 121.36E 33.0 5.9Mb B TAIWAN 99/09/20 18:11:53 23.75N 121.19E 33.0 6.1Mb B TAIWAN 99/09/20 18:16:18 23.69N 121.31E 33.0 6.1Mb B TAIWAN 99/09/20 20:40:08 24.09N 121.95E 33.0 5.1Mb C TAIWAN 99/09/20 21:46:44 23.56N 121.10E 33.0 5.8Mb B TAIWAN Looks like they have had a bad couple of hours...all of the earthquakes have been over 5.0 which is pretty lively.
~MarciaH Mon, Sep 20, 1999 (18:32) #78
From the BBC ONline news: A powerful earthquake has hit Taiwan, killing at least 20 people and causing the partial collapse of a 12-storey hotel in the capital, Taipei. Most northern parts of the island felt the effects of the quake, which has been estimated at 7.6 on the Richter Scale. But it struck in the early hours of the morning, so the full extent of the damage and casualties is still unknown. An official from the Ministry of the Interior told the AFP news agency: "I'm afraid [there will be] more casualties as many people are trapped in collapsed buildings." Taiwan's weather centre says it is the strongest earthquake ever to have hit the island. In Taipei, rescuers are working at the 78-room Sungshan Hotel, trying to pull survivors from the rubble. At least two other buildings in the capital are reported to have collapsed. The US Geological Survey gave the preliminary magnitude of the quake as 7.6 on the Richter scale. Its epicentre is believed to be Nantou, an active earthquake zone in central Taiwan. The earthquake which devastated Turkey last month, killing more than 15,000 people, was measured at 7.4. Warnings of tsunamis - tidal waves which often follow earthquakes - have gone out for Taiwan, Japan and other islands in the region, the Geological Survey said. The quake, which struck at 1.47am on Tuesday (1747 GMT on Monday) caused severe damage to infrastructure and buildings in several cities. Power has been lost in large parts of northern and central Taiwan. But the extent of the damage, especially in remote and mountainous areas, is not yet known. Witnesses in Taipei spoke of continuing aftershocks, buildings collapsing, objects falling off apartment blocks and people fleeing their homes. Radio reports said the central city of Taichung might be the worst hit. The city's mayor said: "This is one of the strongest earthquakes I have felt in my life. Many buildings collapsed and there is damage to roads and other infrastructure". The authorities have warned that, because of the magnitude of the earthquake, aftershocks and tremors may be felt for the next two weeks.
~MarkG Tue, Sep 21, 1999 (04:36) #79
The picture from the air of the collapsed hotel on the news was terrifying. I am hoping this was the only multi-storey building that collapsed, because if the hotel was just symptomatic, the Taiwan situation would look worse than Turkey. Amazingly, only 100 people were apparently in a 12-storey hotel overnight - seems strange? In terms of comparisons with Turkey, if the numbers given so far as dead and injured are correct, I guess the buildings are constructed with quakes in mind.
~MarciaH Tue, Sep 21, 1999 (15:30) #80
Mark, thanks for posting! Those who know about these thing - structural engineers - say the difference between Turkey and Taiwan damage is due almost entirely to buildings on Taiwan being built to stricter codes. That hotel bent and torqued as seen from the air is an amazing and terrifying sight. I can imagine how terrible, having ridden a 7.2 quake here which lasted more than 30 seconds. It was like walking on the heaving deck of a ship as the ground undulated beneath my feet. It is an incredible f eling, and one I do not need to have repeated in my lifetime, thank you!
~MarciaH Tue, Sep 21, 1999 (15:35) #81
According to the news, teams from Fairfax, Virginia complete with sniffer dogs and fiber-optics cameras are on their way to help search for victims. Teams are also in Taiwan from Japan and mainland China and other parts of the US. Karen, has Israel sent their top-notch team there, too? Have not heard as yet. Again, what a terrible job, and I am very thankful such competent people are willing to go and do it.
~MarciaH Tue, Sep 21, 1999 (21:05) #82
Earthquakes and aftershocks continue for Taiwan, and another for Turkey plus one in Portugal just after Gi has gone on holiday, and one for my son in Calidfornia 99/09/20 21:46:43 23.49N 120.93E 33.0 6.5Ms B TAIWAN 99/09/20 21:54:32 38.61N 9.34W 10.0 3.7Lg A PORTUGAL 99/09/20 21:54:49 23.64N 120.94E 33.0 5.4Mb C TAIWAN 99/09/21 07:06:06 23.85N 121.63E 33.0 4.8Mb C TAIWAN 99/09/21 11:49:46 44.84N 149.74E 33.0 5.6Mb A KURIL ISLANDS 99/09/21 14:11:36 13.80N 90.68W 33.0 4.5Mb A NEAR COAST OF GUATEMALA 99/09/21 14:21:03 33.16N 141.42E 33.0 4.6Mb B OFF E COAST OF HONSHU, JAPAN 99/09/21 15:42:48 35.80N 121.26W 5.6 3.6Ml CENTRAL CALIFORNIA 99/09/21 17:38:39 23.90N 121.29E 33.0 5.1Mb A TAIWAN
~MarciaH Tue, Sep 21, 1999 (22:21) #83
~MarciaH Tue, Sep 21, 1999 (22:24) #84
~MarkG Wed, Sep 22, 1999 (02:55) #85
Wonderful plate boundaries map, Marcia! Does your previous list of today's shocks show Richter measures (Ms, Mb, Lg) or are the A, B or C for seriousness)? How come Hawaii gets shocks - is it not safe in the middle of the Pacific plate? What happens to the faultline in the Mediterranean, and the one that heads into Northern Siberia and stops there, do you think?
~MarciaH Wed, Sep 22, 1999 (12:04) #86
The right-hand column is magnitude of the earthquakes on the Richter Scale. According to the source page of those statistics: DEPDepth in kilometers MAG Magnitude, with method used to calculate it: Ml local, the original Richter magnitude Lg mblg or Mn, local or regional magnitude for the area east of the Rocky Mountains Md duration Mb body wave Ms surface wave Mwmoment Q Earthquake Location Quality: A is good, B is fair, C is poor, D is bad
~MarciaH Wed, Sep 22, 1999 (12:23) #87
Since they remove the plate boundary EQ map when they update it, I am posting another one which is static, but still shows all of the boundaries: As to why Hawaii has Earthquakes in the middle of a plate...we are unique in the world for that fact and that we have volcanoes. It seems to be a "hot spot" (as the technicians call it) and as the plate moves across it to the northwest, new islands are formed. Another is forming off of our southeastern flank, but don't contact your real estate agents just yet. It will be several thousand years before it shows above the suface of the sea. The earthquakes we feel are just from the settling of the rock m sses after magma has left a void, or new magma is forcing its way to the surface. Having said that, the strongest EQ that I have been through - 7.2 mag - was from the plate movement across the hot spot. I truly think a lot of the dynamics of the Hawaiian situation is not yet known and GPS, laser measured inflation rates (the mountains actually swell when fresh magma enters the upper levels), and other new techinques may shed new light on the causes. We KNOW all about the effects!
~MarciaH Wed, Sep 22, 1999 (12:24) #88
~MarciaH Wed, Sep 22, 1999 (12:31) #89
Checking other sources about what happens to the Mediterranean plate boundary, it is there, but dives under other strata which have been forced onto it. I think it is the same for the Siberian boundary, as well. Close inspection of the map reveals the continuation of the boundary a few miles in front of the obstruction. (...at least, so it appears!)
~MarciaH Wed, Sep 29, 1999 (13:20) #90
For a comparison of plate boundaries map above and global vulcanism, please check http://www.spring.net/yapp-bin/restricted/read/Geo/2.58
~patas Thu, Sep 30, 1999 (04:53) #91
Marcia, wonderful maps. I'm saving this one as well as the vulcanism one.
~MarciaH Thu, Sep 30, 1999 (12:36) #92
I think they compliment each other...It would be great to have a wall-sized on for reference, I think...
~MarciaH Thu, Sep 30, 1999 (16:58) #93
TSUNAMI BULLETIN NUMBER 001 PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS ISSUED 30 SEP, 1659 UTC THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT CALIFORNIA, OREGON, WASHINGTON, BRITISH COLUMBIA, AND ALASKA. . . . A TSUNAMI WARNING AND WATCH ARE IN EFFECT . . . A TSUNAMI WARNING IS IN EFFECT FOR: MEXICO, EL SALVADOR, ECUADOR A TSUNAMI WATCH IS IN EFFECT FOR: PANAMA, PERU FOR OTHER AREAS IN THE PACIFIC, THIS MESSAGE IS FOR INFORMATION ONLY. AN EARTHQUAKE, PRELIMINARY MAGNITUDE 7.6, OCCURRED 30 SEP, 1631 UTC. COORDINATES: LATITUDE 16.0 NORTH, LONGITUDE 96.8 WEST VICINITY: OAXACA, MEXICO. EVALUATION: IT IS NOT KNOWN THAT A TSUNAMI WAS GENERATED. THIS WARNING AND WATCH ARE BASED ONLY ON EARTHQUAKE EVALUATION. ESTIMATED TIMES OF INITIAL WAVE ARRIVAL AT LOCATIONS WITHIN THE WARNING AND WATCH AREAS ARE: ACAPULCO,MEXICO 1703Z 30 SEP MANZANILLO,MEXICO 1801Z 30 SEP ACAJUTLA,EL SALVADOR 1828Z 30 SEP SOCORRO,MEXICO 1849Z 30 SEP BALTRA IS,ECUADOR 1949Z 30 SEP BALBOA HTS,PANAMA 2150Z 30 SEP LA PUNTA,PERU 2233Z 30 SEP BULLETINS WILL BE ISSUED HOURLY OR SOONER IF CONDITIONS WARRANT. THE TSUNAMI WARNING WILL REMAIN IN EFFECT UNTIL FURTHER NOTICE. RECIPIENTS OF THIS MESSAGE LOCATED IN CALIFORNIA, OREGON, WASHINGTON, BRITISH COLUMBIA, AND ALASKA SHOULD REFER ONLY TO ALASKA TSUNAMI WARNING CENTER MESSAGES FOR INFORMATION ABOUT ANY TSUNAMI THREAT IN THOSE AREAS. David N. Little Geologist IT Corporation Martinez, California
~MarciaH Thu, Sep 30, 1999 (17:23) #94
TSUNAMI BULLETIN NUMBER 3 WEST COAST AND ALASKA TSUNAMI WARNING CENTER/NOAA/NWS ISSUED SEP 30 AT 1836 UTC ...THIS IS THE FINAL TSUNAMI ADVISORY BULLETIN FOR ALASKA, BRITISH COLUMBIA, WASHINGTON, OREGON, AND CALIFORNIA ONLY... NO, REPEAT NO, WATCH OR WARNING IS IN EFFECT. AN EARTHQUAKE, PRELIMINARY MAGNITUDE 7.6, OCCURRED AT 0831 ADT ON SEP 30, OR 0931 PDT ON SEP 30, OR 1631 UTC ON SEP 30. THE EARTHQUAKE WAS LOCATED IN THE GENERAL AREA OF: SOUTHERN MEXICO NEAR 16.1N, 96.8W. EVALUATION: NO DESTRUCTIVE TSUNAMI HAS OCCURRED. NO TSUNAMI WAS RECORDED AT MANZANILLO, MEXICO. NO TSUNAMI DANGER EXISTS FOR ALASKA, BRITISH COLUMBIA, WASHINGTON, OREGON, OR CALIFORNIA. HOWEVER, SOME AREAS MAY EXPERIENCE SMALL SEA LEVEL FLUCTUATIONS. THE PACIFIC TSUNAMI WARNING CENTER IS CLOSING ITS INVESTIGATION AND WILL ISSUE A FINAL BULLETIN. THIS WILL BE THE LAST WEST COAST AND ALASKA TSUNAMI WARNING CENTER ADVISORY BULLETIN ISSUED FOR THIS EVENT. THIS INFORMATION IS ALSO POSTED AT HTTP://WWW.WCATWC.GOV. David N. Little Geologist IT Corporation Martinez, California
~MarciaH Thu, Sep 30, 1999 (18:39) #95
In Hilo, we do not take Tsunami warnings lightly. This is what Hilo looked like the day after the 1960 Tsunami. Information and more pictures from Hilo's very own Tsunami Museum: http://planet-hawaii.com/tsunami/ Suddenly I heard a shout, �Big wave!� The streetlights around us exploded almost in the same instant. I looked up and saw a locally well known fishing boat coming up over the Wailoa Bridge" -- Susan Maeda Veriato on the 1960 tsunami in Hilo, as told to her son Travis [PTM Photo: Polhemus collection]
~patas Fri, Oct 1, 1999 (03:09) #96
Wow! So this is what we would have had if our Giant Wave had been real... As it was, it didn't even fill the pool ;-)
~MarciaH Fri, Oct 1, 1999 (12:55) #97
Indeed! What you cannot see is the human toll. People were washed out to sea, rescued and told terrifying stories to me. Others lost realtives. Our roofs were mostly sheet iron in those days, and the sheets slashed through the water slicing up houses, animals and people. Parking meters on sturdy metal posts were laid flat against the concrete in which they were set. That whole area in the picture has been made into parkland and soccer fields along the bay front and looks lovely. There is a memorial set in the middle background to those whose lives were lost that April 1, 1960. Many more could have been saved had they not thought the warning sirens were an April Fool's Day joke!!!
~MarciaH Fri, Oct 1, 1999 (13:01) #98
It is never just one huge wave. Like the pebble dropped into a pond creates a series of wavelets around its impact zone, so does an Earthquake. It was the third or fourth wave that did the most damage in Hilo. The surging water does more damage as it moves inland, only to suck back out to sea whatever is loose and movable. The next wave deposits it far inland from whence it came. They are terrible waves, indeed!
~patas Sat, Oct 2, 1999 (12:56) #99
Indeed they must be. It is like those aftershocks in Taiwan, almost as ugly as the first quake. I had no idea there had been a quake in Portugal just after I left for Tunisia... Read it here and then had it confirmed... After so much earth motion this year I admit I am a bit worried.
~MarciaH Sat, Oct 2, 1999 (13:12) #100
It is difficult to live in a place with a history of Earthquakes and NOT be concerned... That one in Portugal was minor and north of Lisbon, if I recall correctly...Was there much damage reported? I have seen no follow-up information.
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