http://earthquake.usgs.gov/recenteqsww/Quakes/usweax.htm
What is it about the day after Christian holidays?
What is it about the day after Christian holidays?
Oh joy, another big farking earthquake in Indonesia...
- Thread starter Goober Mcfly
- Start date
That is very sad 
Let's hope this earthquake doesn't create a tsunami like the last 9.0 one did over there....
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Let's hope this earthquake doesn't create a tsunami like the last 9.0 one did over there.....
Reports are it's a 8.7 and already dozens reported dead......
http://story.news.yahoo.com/news?tmpl=story&cid=574&ncid=574&e=1&u=/nm/20050328/wl_nm/quake_asia_dc
http://story.news.yahoo.com/news?tmpl=story&cid=574&ncid=574&e=1&u=/nm/20050328/wl_nm/quake_asia_dc
Latest reports confirm it as an 8.7, it's force was felt 300+ miles from the epicentre and it did signifigant damage to an island off the coast of Sumatra.
The reports of death tolls are anywhere from a few, to dozens, or more. Still, nothing to compare to the last one, which is a good thing.
The reports of death tolls are anywhere from a few, to dozens, or more. Still, nothing to compare to the last one, which is a good thing.
Not Quite an expert but I can readn_v said:
Check out the 3rd paragraph from the bottom:
http://www.prh.noaa.gov/ptwc/wmsg
Not that I’m a seismologist but, there are so many factors at play here that it is difficult to say.Escohort said:
Was the earthquake shallow or deep in the crust?
Was the movement horizontal or vertical?
Was it under water or on land?
What type of seismic waves were mostly generated by the quake? Surface waves (l & r) or body waves (p & s)?
See: http://earthquake.usgs.gov/image_glossary/bodywave.html
http://earthquake.usgs.gov/image_glossary/surface_wave.html
What ratio of p-waves (compressional), s-waves (shear), r-waves (rayleigh) and l-waves (love) reached you?
What are the ground conditions in the area where the damage may occur (i.e. is the building built on rock, consolidated soil or porous and saturated river bed sediments?)
Is the building to be damaged located near the ocean where it can be hit with a Tsunami? (They can travel 1,000’s of km.)
Is there a large land mass between you and the Tsunami-generating earthquake?
Having said all this, a Richter 8.7 earthquake is a very, very big quake. It is currently ranked as the 7th largest quake ever recorded.
http://neic.usgs.gov/neis/eqlists/10maps_world.html
Sorry if this was a bit too technical but you asked for it.
Fascinating show on PBS last night about the 1883 eruption of Krakatoa off the southern end of Sumatra (not far from the recent earthquakes). The immensity of the blast was absolutely staggering.
When the volcano, effectively three volcanos grouped together, finally blew itself apart, it released a force equivalent to 200 megatons of TNT. A one megaton blast would be roughly the same as 78 Hiroshima bombs.
The tsunami created was nearly 40m high.
The final blast was heard over 1/12th of the world's surface, and the shock wave generated in the air, circled the earth 7 times.
Weather was affected across the globe for over three years, sunsets turning blood red at night as far away as Europe.
The eruption ripped the island apart, though the volcanic dome has been rebuilding since 1927. Currently Anak Krakatoa (Son of Krakatoa) is approaching the same size as the volcano was in 1883.
When the volcano, effectively three volcanos grouped together, finally blew itself apart, it released a force equivalent to 200 megatons of TNT. A one megaton blast would be roughly the same as 78 Hiroshima bombs.
The tsunami created was nearly 40m high.
The final blast was heard over 1/12th of the world's surface, and the shock wave generated in the air, circled the earth 7 times.
Weather was affected across the globe for over three years, sunsets turning blood red at night as far away as Europe.
The eruption ripped the island apart, though the volcanic dome has been rebuilding since 1927. Currently Anak Krakatoa (Son of Krakatoa) is approaching the same size as the volcano was in 1883.
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Caused when the volcano collasped in on itself. Fortunately, because the wave was generated from a "point source", the tsunami was somewhat localized.Escohort said:
http://www.drgeorgepc.com/Tsunami1883Krakatoa.html
Escohort said:
fridrikk said:
I am suspicious of a single source explanation for the explosive forces and the Tsunamis. From the reading that I have done over the last couple of years there was more than one tsunami wave from several explosions and I have seen several explanations of what caused them.Asterix said:
The type of lava that comes out of a Krakatoa type volcano is both viscous and rich in dissolved gases (as opposed to the liquid runny types of lava in Hawaii). As the lavas near surface these gases come out of the lava like a warm shaken beer which is uncapped. The high viscosities of the lava can temporarily plug the volcano giving the opportunity for the build up of gas and resulting huge explosions.
The last of these explosions at Krakatoa completely obliterated the island. This explosion alone would have caused a wave but the blowing apart of the island and partial emptying and collapse of the magma chamber under it would have allowed a huge amount of sea water to rush in. The inrush of water would also create a wave. Then that water would be exposed to a very large amount of molten rock. It would flash to steam and create a huge steam explosion. The instantaneous conversion of say 1 cubic kilometre of sea water to steam would create an explosion which could easily rival any nuclear weapon.
So it is possible that all of these affects contributed to the explosions and tsunamis with earlier explosions being mostly the lava and later ones a mixture. The PBS program seemed to debunk the potential for a steam explosion because of the coarse size of the pumice fragents exposed in a rock outcrop of the debris left behind after the explosion (steam explosions create fine pumice). However, I noted that only the bottom metre of about 20 m of rock was coarse and there were known to be several explosions. This observation fits with the summary of other peoples speculations above. Several people believe that that at least some of the later explosions were steam related.
