Depths of the lake

December 23, 2018

A visit to Crater Lake in the US triggers an essential debate…

Depths of the lake

The movie was over. I had questions. Before putting on the movie the park ranger had offered to answer any queries I might have. The movie was about the Crater Lake, a deep freshwater lake created in the bowl of an inactive volcano in Oregon, USA.

The beautiful animation showed how the lake was formed when an erupting volcano lost most of its crest because the lava started coming out from all around the volcano and not just the top. Geologists estimated this event happened 7,700 years ago. I was curious about this exact number.

How were they so sure about 7,700 years? Why not 5,000 or 10,000, or to say that it might have happened somewhere between 5,000 and 10,000 years ago?

The movie also included an interview by a man from a local Klamath Indian tribe. Indigenous people did not put pen to paper before Europeans came to the Americas but their oral history goes back thousands of years. According to the interviewee, the tribe’s oral history purported that Crater Lake was formed when underground monsters fought with powers from the sky. In addition to written documentation of events, calendars were also not maintained by the locals at that time. Life was to be lived one day at a time.

Scientific inquiry established that human beings crossed over from Siberia to reach present-day Alaska and onward to the rest of the Americas almost 20,000 years ago. If the Klamath tribe experienced the formation of Crater Lake, then the ‘fight between the subterranean and the celestial forces’ must have happened within the last 10,000 years (say it took 10,000 years for human beings to transform from a hunter-gatherer group to a well-defined tribe laying claim to the area around the Crater Lake).

Outside the audio-visual room, I found the man I was looking for but unfortunately, he did not have a very good answer about how the geologists came up with such a precise age of Crater Lake. The man spoke vaguely about how ash found in other places in the world was connected back to Crater Lake but did not say anything specific about the 7,700-year number.

I left, having decided to do my own research on internet. There was a lot of information about Crater Lake, but nothing about how the exact age of the water body was calculated. I did my own calculations starting with the depth of water in the lake.

Crater Lake has a steep boundary. Not much water enters the lake from outside -- whatever rains right on top of the lake and a small amount landing on the steep walls of the crater ends up there. There is no water flowing out of the lake. You can reason that the water level of the lake has been increasing from the day the cavity was formed. Crater Lake gets an average of four feet of snow every year. The lake is 1,949 feet deep. Divide 1,949 by 4 and you get 487 years. The hollow cavity left by a collapsed volcano started filling up in 1531 AD -- 39 years after Christopher Columbus discovered the New World.

…the tribe’s oral history purported that Crater Lake was formed when underground monsters fought with powers from the sky.

But then you revise your math. You remind yourself that one feet of snow is not one feet of water. One feet of snow in most cases is just four inches of water; so, you multiply your previous answer by three and calculate the lake to be 1,461 years old. But even that answer is erroneous.

Yes, there is no water flowing out of the lake, but there is evaporation and there is seepage. How much water is being lost due to evaporation and seepage? 25 percent or 50 percent of the intake? With 50 percent water losses the age of the lake comes out to be 2,922 years. And that is where my water-in-the-lake-deduced mathematical calculations stopped.

The point to appreciate here is the attitude of incredulity in analysing scientific data. Science has an egalitarian nature. In pursuit of the scientific facts, we are all equal. Anyone can challenge findings presented by any group of scientists. Compare this attitude to what you see in belief systems. There, you must revere certain people and you must not ask too many questions.

I have gathered an interesting crowd on Facebook. In one of my recent posts on social media I alluded that the religious beliefs we hold sacred today have been passed on to us through several generations -- believing in them is not only believing in the ‘beliefs’ we hold true, but also believing that the original message has been conveyed unblemished, generations after generations.

One of my Facebook friends did not like the thought. His retort went like this: "The belief in the sanctity of the message through centuries is not unique to religion; the same happens in the field of science. No one alive today has met Mr. Newton, but we still believe in his theories."

I found it incredulous that in this day and age there were people who did not see the profound differences between science and beliefs. Science is about brutal honesty, about criticism, about raising questions, about being doubtful of any presented theory. The scientific approach is diametrically opposite to religious beliefs. The students of science do not respect Newton because they blindly believe in the laws of motion. They admire Newton because they find those laws to be true. Two centuries after Newton died, human beings were able to send rockets in outer space by calculating escape velocity using Newtonian laws. Those calculations would have been still correct without knowing anything about the man who gave us those mathematical equations.

Oregon’s Crater Lake deserves a better name since ‘crater lake’ is a generic term used for any lake created in the caldera of a collapsed volcano. There are many crater lakes in the world. The most recent was formed in the Philippines after the Pinatubo eruption in 1991.

By the time we reached Crater Lake, it had stopped snowing but there was snow on the ground. The white background provided a photogenic backdrop, and further added to the beauty of the lake. In the absence of any water going in or out of the lake, this jewel required a re-definition of the word ‘pristine.’

Standing on the rim of the erstwhile volcano, I looked down at the water. It reminded me of how a few years back I had seen the sulfur-spewing Mount Bromo volcano in Indonesia. But here there were no menacing sulfur fumes; the hole was filled with sweet water. Standing there, awestruck, irrelevant questions faded away. How old the lake really was? Who cares?

Depths of the lake