The clock is ticking in Sumatra

Nothing weird is happening? Two quakes of 8.7+ in the same region only 3 months apart. 242 quakes of 4+ in Northern Sumatra in 30 days which is better than 1/3rd of the global quakes over 4.0 and you think there is nothing weird. Large quakes are running at about double what is normal but you think there is nothing weird? A few volcanos have responded already and now 2 more have been raised to the 3rd alert level in Sumatra and nothing is weird? BTW... I don't recall the native name for it but one of those that just had the alert level raised was Son of Krakatoa. There has been a report of activity being triggered in Toba Lake by one of the quakes and nothing weird is happening.

Some people might over react but to think that nothing is weird about this just strikes me as falling asleep at the wheel.

Anak Karakatoa (literally Krakatoas Child, or as some put it Son of Krakatoa) is active too is it? This isnt too abnormal as it is usually quite active. The island of Krakatoa has rebuilt its self at least once before into a large mountin in the space of 1500 years, so its activity is normal in its rebuilding cycle... Do you have a link for this Indy?

There is also a Volcano in Java (Sth E of Sumatra) becoming active, this is on the same fault, but i dont think its triggering is a direct result of the Sumatra Quakes...

Here you go...

www.indonesia-relief.org...

"Jakarta, Detikcom - On Wednesday, Indonesia's Vice President Jusuf Kalla asked people living in area near of mount of Anak Krakatau (Child of Krakatoa) and Tangkuban Perahu to prepare from being evacuated. The VP announcement released as the danger level has been raised to level III on both volcanoes. "

While at some point before modern history things like this may have happened we must also wonder what else happened at this time. How far did the problem go? What is being observed now is unprecidented in modern times.

time to move these people out of the area.large ships needed to get these people out of this whole area.what country wants to get the ball rolling?one of the great problems where do we put whole countries displaced people.this might be a good u.n council question. for the future will be full of displaced people.

As far as i know Krakatoa has had two climate changing eruptions that have been confirmed.... one in 530 or there abouts and one in 1883... Anak Krakatau, essentially being the same volcano, isnt likely to have another huge one like those two for quite some time... but it is likely to have smaller eruptions as it is one of the most active volcanos around... it regularly blows itself up and rebuilds itself.

Moving the population isnt an option, especially if your thinking the whole population of indonesia... 200 000 000 people is alot... also in the regions these volcanos are erupting, alot of the popultaion is pretty much isolated with nothing but jungle roads linking them to the world outside...

[edit on 14-4-2005 by specialasianX]

Originally posted by Indy
Nothing historic is happening? Two quakes over 8.7 in the same general region barely 3 months apart. Want to rethink your comment?

No I wouldn't thankyou.

We may have seen what appears to be an historic event to us, but geologically speaking this is not anything unusual, and this is my main point. Earthquake activity waxes and wanes in tectonically active regions, its a fact of life. It does not spell some sort of "beginning of the End" despite what you might think. How many times do I have to go over this.

Originally posted by Indy
Nothing weird is happening? Two quakes of 8.7+ in the same region only 3 months apart. 242 quakes of 4+ in Northern Sumatra in 30 days which is better than 1/3rd of the global quakes over 4.0 and you think there is nothing weird.

Indeed, its not weird.

Large quakes are running at about double what is normal but you think there is nothing weird?

How do you figure its double? The tightest resolution for earthquake activity on a regional scale is probably a year. This has been an average year.

. There has been a report of activity being triggered in Toba Lake by one of the quakes and nothing weird is happening.

Again, indeed, nothing weird. Earthquakes and volcanos are not weird.

Its entirely possible, tho not certain, that if humans had a clearer understanding of the system (supposing there is one) that they'd be able to say that these earthquakes should precede some volcanic activity.That, in itself, wouldn't be weird.

When Mt. St. Helens erupted it was preceded by small earthquakes.

However, there are earthquakes in that region because of intersecting tectnoic plate margins. So the analogy to small earthquakes that precede volcanic eruptions is not a good one.

Th best indicator that there might be some volcanic activity in the region, is, well, some of the volcanic activity that is starting.

But the big quakes have nothing to do with anything, certainly not systematically. Again, look at the information, it shows that there is a heck of a lot more tectonic activity all over the globe than people realize. Everyone is scarred because of the tsunami. Fear, however, is not a useful emotion in this case, and its obscuring any estimations of what is and what is not going on there.

to all you "nothing's happening" people

I understand your argument that these types of events are nothing new to earth and something that has been happening on and off for milleniums. But it's rather disturbing to hear you say not to worry, nothing is going to happen, to people living now, when there is a possibility that something could seriously happen within our lifetimes.

So yes I agree it's not strange in the "big picture of things" and will not bring the end of the world. I'll say this again, no matter what religion you believe in, the world will never end, it is mankind and life "as we know it" that might be changed forever due to one of these natural events.

But it is strange on the local, day by day basis for the people living now in the areas being affected.

Make no mistake, the region is dangerous, and a lot more people are going to die from more events. Similarly, there are going to be a lot of houses destroyed in the US from tornados/hurricanes during the course of this year and towns and villages might very well be wiped out by flows of lava.

To think that, because of rather normal geological activity tho, that indonesia's going to sink beneath the waves or that the whole region is going to become of steaming slag heap is irrational tho.

So are there going to be disaster, yes. Is the world going to crush and crumple in a catacylsm, no.

But it is strange on the local, day by day basis for the people living now in the areas being affected.

Undoubtedly, have the very earth underneath you move in waves and split upon is, at the very least, a bit peculiar.

Turkish Press

I found this as highly relevant to my posting in the Volcano Watch 2005 Section.

I think Indy is covering this very good!

Of course in earths lifespan things like this happen... as we stated Krakatoa already has had two huge eruptions... Toba erupted 74000 years ago last (i'm not sure how regularly Toba erupts), and it was a HUGE eruption. Its one of these 'supervolcanos' that seem to be getting alot of attenttion these days... while i concede this Sumatra activiy is like to die down and come to nothing, as these things often do, the fact that a supervolcano is inevitably going to erupt at some point is daunting.

Also on the note that these quakes dont indicate any danger... i feel that is not neccesarly true. Prior ti Krakatoas 1883 eruption, for around three months, there was alot of seismic activity... Earthquakes, minor eruptions of the island etc etc... now while i'm confident Krakatoa wont erupt as it did in 1883 for a long time (the pressure hasnt built up to those levels as yet) I'm concerned that another volcano on the fault may be building that pressure. As the Indo-Australia palte subducts under the burmese (?) plate it takes with it, with each earthquake, and substantial amount of water... this water gets caught in subterranean magma chanbers and turns into steam... this steam builds up in pressure untill it is sufficiently vented... usually vias volcanic eruption. Now if one of these chamber has been building up with steam (and of course magma) for several centuries (or millenia), when it does vent it all out, it is likely to be in the form of a large explosion... this is exactly what hapened with Krakatoa 122 years ago... Also the Archipelago that is indonesia is no stranger to these large eruptions ans the whole country is effectively on a fault line...

This wont be 'the end of the world' as stated, our race will die out or move on before the end comes... but a large eruption of Toba could result in climate changing events... keep in mind the last eruption caused a 1000 year ice age... better to keep my eyes out for these things and be 'paranoid' than ignore the signs and be suprised... not that we can really do anything about it.

It may have been stated before but Tambora also falls in this fault line. But like Krakatoa it hasn't even been 200 years since it last went off.

I forgot about Tambora... but as you said i would deem it relatively low risk... But there are alot of dormant and active volcanoes on sumatra and Java alone... and any one of these could be a pressure bomb waiting to explode.

I'm not sure about a supervolcano errupting but I would't be surprised to see a erruption similar to Mount Pinatubo back in 1991. (using this one just because it's a well known volcanic erruption.) Though this means almost nothing but here is the quake information preceeding pinatubo and a graph for Mt. St. Helens. Similar volacoes to what is in Indonesia i believe.

Numerous small earthquakes of the type that record fracturing of brittle rock (fig. 11A) continued through May. The earthquakes were generally too small to be felt, except very locally. For 1,800 earthquakes located between May 7 and June 1, magnitudes were less than 2.5. These earthquakes were strongly clustered in a zone between 2 and 6 km deep, located about 5 km north-northwest of the volcano's summit (fig. 12). Possibly, they recorded adjustments of the earth's crust to stresses
generated by growth or pressurization of a shallow body of magma.

USGS on Mount Pinatubo

Mt. St. Helens Seismicity graph

Notice the depth of the quakes. With the Mt. St. Helens Graph almost all are smaller than 10km depth.The depths of the quakes in indonesia are always around 20 Km or more. The seismology equipment weren't even used on Mt. St. Helens until just recently before the 1980 erruption.
Talang has shown some small shallow earthquakes, so if anything an erruption with some pyroclastics is about all I really fathom though.

Also, it's not so much the lava that gets you. It's the pyroclastic flows and subsiquent mudslides from one of those erruptions.

Originally posted by silentlonewolf


Also, it's not so much the lava that gets you. It's the pyroclastic flows and subsiquent mudslides from one of those erruptions.

Not to mention dust and ash thrown into the air if the eruption is large enough... but thats a very 'what if' scenario

There was a large and very shallow quake only miles from Toba Lake today. A 6.1 quake only 10km deep.

Wooow. That's close, and not too deep to be close to a supervulcano either!

I found another quake. It is a pretty recent one, too...

thestar.com.my.../2005/4/17/asia/10714296&sec=asia

By the indonesian island of Nias. Measured to 6.3!

The scary thing is, my family lives on the east coast of Malaysia.. which would be pretty #ed up if Toba went off... bot that it really matters, i think the whole planet would be pretty screwed.

On a side note... we finally got that Supervolcano show last night here in Aus... scary stuff...

They just got a 6.9 in Northern Sumatera, Indonesia... Looks like things may be picking up...maybe not.. Hopefully this doesn't get worse.

Originally posted by silentlonewolf
Notice the depth of the quakes. With the Mt. St. Helens Graph almost all are smaller than 10km depth.The depths of the quakes in indonesia are always around 20 Km or more.

Cause of difference should be quite logical.
In case of quakes before volcanic eruptions it's pressure and movement of magma near surface which causes them.
While in case of tectonic earthquakes cause is often stress in lower parts of crust.

And here's something from USGS:
Descriptor Magnitude Average Annually
Great 8 and higher 1
Major 7 - 7.9 17
Strong 6 - 6.9 34
Moderate 5 - 5.9 1319
Light 4 - 4.9 13,000 (estimated)

Number of Earthquakes Worldwide 2005
Magnitude Number
8.0 to 9.9 1
7.0 to 7.9 2
6.0 to 6.9 73
5.0 to 5.9 762
4.0 to 4.9 5295
As of 12 May 2005

[edit on 14-5-2005 by E_T]