Article:
What Are Men to Rocks and Mountains?
By Mike Searle
The Open Magazine - 19 October 2013

Field geologist and Earth Sciences Professor Mike Searle shares his expertise on the shifting plates beneath our feet.

Colliding Continents: A Geological Exploration of the Himalaya, Karakoram & Tibet is the outcome of more than 30 years of research by Mike Searle, currently Professor of Earth Sciences at University of Oxford. Combining geological fieldwork with mountaineering expeditions and unforeseen adventures, the author has produced a seminal narrative on the geological history of one of the most active collision zones on earth. Stretching from the Arabian Sea along the great mountain ranges of Pakistan, India, Nepal and Bhutan, then south through Myanmar and Thailand to the great volcanic arc of the Andaman Islands, Sumatra and Java, this zone’s story features some of the highest mountains in the world, spectacular geology, earthquakes and tsunamis.

An interview:

Q: At 55 mm per year, the ongoing collision between the Indian and Asian plate is currently the fastest one on earth. What is the impact?

A: India collided with Asia 50 million years ago, and the whole Himalayas are a product of the shortening and thickening of the crust. It is why the deep rocks are coming up as high mountains. The Indian plate is actually subducting [or diving] under Tibet. And it’s the Indian lower crust that is holding up the southern part of Tibet.

Q: Are we engaging in potentially dangerous activities in geologically sensitive zones?

A: Yes. It is plain stupid to build a dam in an earthquake zone. There was one planned on a faultline in the Chenab valley. I don’t think it was ever commissioned because they realised it was breaking even before they built it. It is a classic example of a government going ahead with a project without consulting a geologist.

There was also a huge dam built on the Indus in Pakistan that was silted up within 10 years. Dams have a short lifespan. It is much better to make smaller, hydro-electric type generation projects.

The Three Gorges dam on the Yangtze river in China is another example of a massive amount of construction for [what is] probably short-term benefit. China has also built a city called Kanding in Western Yunnan on the most active fault of Tibet. Three earthquakes of magnitudes 8 have occurred there in the past 80 years. It’s just a matter of time before the whole city is destroyed.

We also know there is a big seismic gap in NEPAL where there hasn’t been a big earthquake for nearly 70 to 90 years.

There are three ranges in Tibet the size of the Alps. We have no idea what’s in them. Almost no geological work has been done. So we know more about the moon than we know about eastern Tibet. It is roughly centred at KATHMANDU. Even a small earthquake could bring the city down, which is built on an old lake. As soon as you propagate a seismic wave, the sediment will flux and turn into jelly. Kathmandu is a disaster waiting to happen, like the Mexico City earthquake. It wasn’t a big earthquake but it flattened the city because it was built on old lake sediment.

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Image:

Photograph of the Himalayas near Tibet from the 'Strachey Collection of Indian Views', taken by Samuel Bourne in 1866.Samuel Bourne, the bank clerk and amateur photographer arrived in India in 1863 during the early years of commercial photography. Photographs taken during three expeditions to Kashmir and the Himalayas between 1863 and 1866 demonstrate his ability to combine technical skill and artistic vision.

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