the last volcano!

In the last few posts I have looked at the volcano exclusion zone and tried to relate it with the maximum height to which a volcano spews ash. In the last one I looked at Mount Mayon.
Unfortunately for my explanation, the exclusion zone in Mount Mayon is related to pyroclastic flows. Ash, it seems, is generally not a danger. Only in rare cases does it cause trouble - to aeroplanes, for instance. The above conclusions are based on downloads from the net:

http://www.vulkaner.no/v/vulkinfo/tomhaz/manyhaz.html

When a person thinks of a volcanic eruption, they always think of a huge cloud of ash sweeping high into the air. In reality, this ashfall is a relatively minor hazard. It rarely claims lives.

The most explosive eruptions send out great clouds of ash in enormous so-called 'plumes'.
In fact, scientists use the height of the ash plume to calculate the explosivity of an eruption.
A minor plume, less than 100m in height, is common for a Hawai'ian volcano, while when a
plume exceeds 25 km, the eruption is far more explosive. Examples of these more explosive
eruptions include Mount St. Helens in 1981, Krakatau in 1883, Tambora in 1815, and an
ancient eruption of Yellowstone caldera 2 million years ago. The following brief table is known
as the volcanic explosivity index. It is used by volcanologists to calculate an eruption's force,
as well as its type. These are placed in order of increasing explosivity.

DESCRIPTION	PLUME HEIGH	VOLUME OF ASH	EXAMPLE
1) Non-explosive	<100m	1,000m3	Kilauea, Hawaii
2) Gentle	100 - 1,000m	10,000m3	Stromboli
3) Explosive	1 - 5km	1,000,000m3	Galeras, 1992
4) Severe	3 - 15km	10,000,000m3	Nevado del Ruiz
5) Cataclysmic	10 - 25km	100,000,000m3	Galunggung, '82
6) Paroxysma	l >25km	1km3	St Helens, '81
7) Colossal	>25km	10km3	Krakatau, 1883
8) Super-colossal	>25km	100km3	Tambora, 1815
9) Mega-colossal	>25km	1,000km3	Yellowstone

Thus the height of an ash plume is an excellent indication of the power of an eruption. But there are individual hazards based around the ash also. The Mount St. Helens' plume extended over 20,000m into the air, while the eruption of 1956 Bezymianny, in Russia's Kamchatka peninsula, generated a plume 45,000m in height.

The hazard first became evident at Galunggung in 1985. It was found that the ash interfered with the functioning of aircraft, and chaos was barely prevented. The hard and angular particles of ash abraded windshields; fine particles, deposited inside the plane's engines, reacted with water to produce a corrosive acid. It has since been found that it is possible for ash to actually melt inside the engines, creating a sticky fluid that stalls them.

During a 1989-1990 series of eruptions, Redoubt Volcano, Alaska, spewed enormous clouds of ash into the air. On December 15, 1989, a 747 (KLM flight 867) flew into the ash cloud. An accident was barely prevented; had a crash occurred, all 231 passengers would have been lost. The eruption of Mount Spurr in 1992 posed similar problems.

The hazard became most notable in 1991 with the catastrophic eruption of Mount Pinatubo. Ash from this volcano travelled more than 5,000 miles to the east coast of Africa, interfering with some 20 aircraft as it did so. In total, the ash from this eruption damaged over 40 planes, causing damage of over $22 million.

volcano contd.

In my last post, I tried to calculate the radius r of the exclusion zone around a volcano from the maximum height hm to which the volcano can send ash etc into the atmosphere, saying that r=2(hm) - and compare it with actual data. The basic physics is probably ok but I neglected the height h of the volcano. In that case you have to solve a quadratic, and take the positive root. The equation is more complicated and it is easier to just run a program. One interesting feature is that when h=0 the maximum range occurs for 45 degrees (from the horizontal), but as h increases, the optimum angle decreases till it is about 36.5 degrees for the 2,500 metre high Mount Mayon in the Philippines , and for hm>=3,000 metres, I got r=8,123 metres. This value of hm was recorded on 24th Feb.2000 for Mount Mayon (aircraft passing by were warned away from the volcano) - and an initial 6 kms radius of exclusion zone was expanded to 8 kms. This is in good agreement with the calculation, but it might still be a coincidence. One would need more data supporting it - or an authoritative statement (backed by data!).

volcano exclusion zone

A couple of months ago a news item on BBC World News was that a volcano in Indonesia was sending ash and rocks 4 kms up into the atmosphere, and the authorities had evacuated the surrounding area and declared an exclusion zone with a 8 kms radius.

The ratio of 2 didn't appear to be a coincidence so I checked my physics book.
Sure enough, if the maximum height (for a projectile sent straight up) is v^2/(2g), then the maximum range is v^2/g, the latter corresponding to a 45 degree inclination, v is the initial velocity and g the acceleration due to gravity.

However, this neat picture based on my memory is contradicted by:

http://www.volcanolive.com/volcanolive.html

a) Residents living in 10 villages within an 8 km radius of Gamkonora volcano in Indonesia have been advised to evacuate after an increase in activity. Frequent tremors have been recorded at Gamhonora's crater since Sunday. Ash was emitted to an altitude of 8000 ft today. The volcano alert status has been raised to maximum level 4 (7th July 2007)

b) 12.77 N, 124.05 E, summit elevation 1565 m, stratovolcano
Tuesday 31st July 2007
Bulusan volcano erupted at 9:37 am (local time) today, covering nearby villages with ash. The eruption frightened residents who ran out of their houses. The ash column reached a height of 5km and drifted NW. The military is expected to enforce an evacuation of people from areas close to Bulusan. There is a 4 km permanent exclusion zone around the volcano.

So was my memory in error? Is the simple derivation relevant or irrelevant? Right now: I dunno.

A fable based on the Israeli invasion of Lebanon

Fly, Crow, Fly!

Princess Jael was woken from her beauty sleep early in the morning by the harsh cawing of crows. She was, understandably, furious. She had been rudely awakened yesterday as well in the same way. This was intolerable. Something had to be done. Her bedroom in the new palace was just next to a cedar forest, and the crows roosted in it. Nasty, dirty, black crows that made a very unpleasant sound – and didn’t please the eye either.

Obviously they should all be shot, since they were literally blots dotting the landscape. Unfortunately, Jael recalled, there were these tiresome regulations, rules and conventions created in Geneva that protected all species, including, surprisingly (considering that they were hardly endangered!), crows. Faugh!

Jael was proud, determined, and intelligent. The conventions could not be disobeyed, but they could be evaded. She would have to think of something legal – but effective, nonetheless. She spent the morning just wandering around, but by afternoon, she was hard at work in her workshop. She had a plan.

The noisy crow was named Hassan. Hassan lived in the cedar forest, with his father Omar Sharif, and a pretty large crowd of uncles, aunts, cousins, and what-have-you. Omar told Hassan that their clan had lived in the forest from time immemorial. It was customary to greet the arrival of the sun in the morning by bending down one’s head and saying one’s prayers. Similarly, the departure of the sun at sunset had to be acknowledged with the same reverence. This was a sacred duty of all worshippers. This was the way it always had been, and the way it always would be.

Plan A: Jael got hold of a laser dazzler. Now, all laser dazzlers are set for eye-safe levels. But Jael was going to set the level a bit higher than that – after all, mistakes do happen! It worked in a way: Omar was blinded. It wasn’t very effective because Omar warned the other crows and they fled into the depths of the forest, where they were difficult to spot.

Omar told the clan that they would have to be very careful. This white witch that had recently made her palace next to their beautiful forest, who knew what she could or would do? It was war. But what could the helpless crows do? They had no arms. In another way, Jael’s retaliation had an unintended effect: Omar’s status was greatly enhanced: he was now a blind prophet. He sat perched in the middle of the forest ranting and raving, preaching hatred to any crow that would listen to him – and there were many.

A lot of them started a practise of dive ‘bombing’ the palace – but all that they succeeded in doing was making the palace rather dirty. Jael tried the laser blinder on these crows, but its effectiveness was much reduced since the element of surprise no longer existed.

Plan B: Jael decided to make a flying robot. Jael knew very well that making a flot that could match the flight of the crow would be very difficult-to-near-impossible. So she just aimed for speed. Her flot would fly faster than sound. What would that do? Create a sonic boom. A very loud boom. Rather disturbing, actually. It would be poetic justice. Whip the crows into shock, that was the idea. First Jael would make one flot, and then a whole fleet of flots could be made by her attendants, David and Benjamin.

Jael’s flots were very good indeed. The sonic booms generated by her flots really shook up the forest. The crows didn’t get a minute’s rest and they all became jittery and neurotic. There was talk of evacuation, migration, despair and defeat. Hassan decided to tackle the flots head-on. Literally. He got a sharp stick in his beak and then hit the flot with it. At high speeds, the collisions were hurtful to Hassan, but fatal for the flots. Soon the other crows picked up the trick, and reduced the fleet of flots to rubble. Jael made more flots, smarter flots, faster flots…there were as many crows killed as flots destroyed, but it was clear that this war could not be won: there were, alas, just too many crows.

Jael came up with the idea of psych warfare. The sound of frightened crows frightens crows. She recorded the alarm calls of the crows and played it back to them at very high volume, at night. This technique was also very effective, at least for a while. Gradually the crows became used to this too. In fact, the crows started making mocking versions of her tapes as a lullaby. Jael tried using ultrasonics, but the crows were unfazed – only Jael’s dogs became restless and barked all the time. She had to abandon this method.

Jael was, by this time, almost running out of ideas, and this was galling. She was thinking of defying conventions and either cutting or burning the forest down. Then she hit on the idea of genetic engineering. She wasn’t good at this but her Uncle Sam might be able to help. After all, Uncle Sam (and a few others) had Promised all of this Land to the Chosen (Jael’s) people – never mind the minor detail that her ancestors had left almost two millennia ago.

Finally, she came up with the idea of a Quickfix Tree. This genetically modified tree would be so sticky that the crows and their nests would stick to the sap and be unable to escape. Uncle Sam told Jael that this was an excellent idea but it would be easier to genetically modify the cedar trees. This way no new trees would have to be planted and the existing trees would become a death trap for the crows.

Jael was very hopeful. She sent Uncle Sam the cedar samples that he needed. Uncle Sam told her that it would take him at least a year to figure out how to modify the cedars, and the tree ‘therapy’ itself would be expensive, because each tree in the forest would have to be injected with the agent. Jael thought that this was sounding more like a Slowfix than a Quickfix, but she told Uncle Sam to go ahead anyway. Both Jael and Uncle Sam agreed that any problem had a technical solution: find the right force multipliers, and then, just do it!

Uncle Sam suggested to Jael that it would be more economical to modify only a part of the forest - not the whole damned thing. He told Jael that there was a river in the forest called the Litany River. If she modified the forest only as far as the Litany River, the sounds of the crows would cease to disturb her. The distance to the Litany, as the crow flies, was about 10 miles.

Jael and Uncle Sam unilaterally decided that this compromise plan was the best by far – since it respected the ‘rights’ of the crows and Jael’s undeniable needs, giving them both weightage. Uncle Sam says that all this Geneva stuff is old-fashioned and redundant in our times.Why did they not talk to Omar and Hassan? Talk? How do you talk to crows?

Hassan claimed that the crows had won the war (which was true, in a way, since they were many crows still alive). Jael said that she (and her friends, few but powerful) had won. This is how it stands today: a real win-win situation.

human memory

This is another ‘blog-of-one’- a blog destined to be read only by the writer – that probably constitute 99% of all blogs. According to Lotka’s law, only a minuscule proportion of all bloggers will have significant readership.

The upside of being a blog-of-one is that you enjoy considerably more freedom in your thought processes than if you were trying to communicate effectively with others. Since you are talking to yourself, you can loudthink a lot of zany ideas and ride your hobbyhorse untroubled by extraneous considerations. You can be brief to the point of being cryptic, assuming that if you ever read this stuff again, you will be able to retrace paths through tangled thickets.

The question that I want to pose here is this: when will the amount of information exceed the capacity of humans to comprehend it? Or have we already passed this milestone? The motivation for asking this question is simple: we are assured that information grows at an exponential rate, with a doubling time of about 5 years (?). Human population also grows exponentially with a doubling time of about 30 years – and some demographers would argue that population should stabilize within the next century or so (?). Thus, at some point one would expect information overload. A few centuries ago, the so-called Renaissance Man was a colossus who could span the entire range of human knowledge. Today a researcher finds it difficult to keep up with even one field of study.

Note, however, that this question can be answered in several different ways: there is no unique answer. The other peculiar thing is that it requires one to ask and answer several related questions: What do we mean by information? What is the capacity of an individual human (this capacity, if it is limited, may also vary from person to person)? Does this vary with lifespan? How much do we rely on computers to search for information? Can we rely on computers? How do we store all this information?

Do we define information as raw data or as processed data? If the former, this would include all the bits and bytes that are used to digitize images (photos, videos, movies), 0’s and 1’s in assembly level computer programs, many forms of digital data (e-mails, web pages, instant messages, phone calls etc) and a huge amount of analog data that would have to be digitized at some resolution. This is the approach reported on in an article in the Hindu (3^rd March 2007), entitled:” Time to learn your exabytes and zettabytes”, which quotes from a report by a technology firm IDC. IDC determined that the world generated 161 billion gigabytes (161 exabytes) of digital information last year. This is considered to be three million times the information in all books ever written. Previously, UC Berkeley researchers had estimated an amount of 5 exabytes for global information produced in 2003. This estimate included analog data (which IDC did not) such as memos and radio broadcasts, but only considered original data – not counting the data that was merely copied (unlike IDC). Had IDC excluded copying, the data would come down to about 40 exabytes. IDC estimated world storage capacity of information at 185 exabytes last year, projected to increase to 601 exabytes by 2010 – as compared to 161 exabytes generated last year, with 988 exabytes (close to 1 zettabyte) in 2010. The gap may be reduced if not all information is stored: e.g. if phone call records more than 5 years old are deleted.

Clearly, this type of digital data is going to increase enormously. However, if we refer to only processed data as information, this amount is going to be considerably less. The question then changes to: how do we compress data to answer specific queries or search for particular patterns? For example, if we identify a weather phenomenon as El Nino, that cluster of data that repeats in space and time qualifies as information – not the raw data of surface sea temperatures. This argument has two problems: the same primary data can be analyzed in different ways. The number of different ways is not indefinitely large, but each time, one has to return to the primary data for validation. Secondly, there may be cases where the data are inherently incompressible: e.g. when we have phenomena described by irrational numbers or by fractals. The second class of problems may not be serious in most cases because of the existence of noise and fluctuations in the real world, but one may not rule the argument out in principle in all cases.

In a sense, the information explosion may be considered along with Malthus’s prediction of a population explosion. There could be a mapping of food on to population, and population on to information. Contrary to Malthus, human population has stabilized without major disasters. However, information continues to be added at an exponential rate and shows no signs of stabilizing.

It may be asked: does information always increase monotonically? Examples to the contrary include the burning of the library of Alexandria, the fact that formats may become unreadable, scripts unreadable and whole languages lost irretrievably (the Cretan and Indus Valley scripts are instances). However, the overall trend despite such glitches seems to be one of increasing information. The so-called Dark Ages were dark in Europe, but not so in the rest of the world. Today information is scattered world-wide, but the places at which the generation of information is fastest may still shift around.

As the human species pushes the envelope, for example, to newer environments (outer space and the oceans, maybe manmade cities/worldlets in these places), the amount of information generated is bound to increase in its attempt to understand these new possibilities. These new places may also require new sensory modalities or means of motor control (remote or autonomous) which will also expand horizons.