The oceans are full of many abysmally deep
places. Tonga Trench is one of them. It is, in fact, the 2nd deepest
place on Earth, the first being the Mariana Trench.
The deepest point of this trench is 35702
ft or 10882 m. It is only 114 m less than the deepest point on Earth,
Challenger Deep of Mariana Trench.
The Tonga Trench is situated in the
southern part of the Pacific Ocean. The trench lies parallel with the eastern
shore of Australia. It is can also be joined with islands of New Zealand with a
straight line on a map.
The Tonga Trench is followed by the
Karmadec Trench in the south. These two forms the active Tonga- Karmadec
subduction zone.
Origin
The trench is created due to tectonic
activities. It is situated on a convergent plate boundary. A convergent plate
boundary is the place where two tectonic plates meet with each other and some
destructive activity takes place.
This particular convergent plate boundary
is known as the Karmadec-Tonga subduction zone. It is a subduction zone where Pacific
plate is going under the Indo-Australian plate. As a result, the Pacific plate
bends towards below and the Indo-Australian plate is uplifted. That tectonic
event has created the Tonga Trench and some other trenches and ridges.
Important Tonga Trench Facts
The Tonga Trench is an 850 miles (1,375 km)
long channel. Every point of the trench is not 10 km deep. The average depth is
6000 m or 20000 ft.
The deepest point of the trench is known as
Horizon Deep.
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| Tonga Trench Satellite Image Source: Google Earth |
In the Northern Tonga Trench, the convergence
between the Indo-Australian and Pacific plate is going on at a fast rate of 9
inch per year. It is too fast for a geological timescale where we have to
consider millions of years?
Active tectonic activity around the Tonga
trench results in frequent earth quakes around the area. The island of Tonga experience
around 350 quakes per year. Often, the large earth quakes generate tsunamis.
The Tonga trench is so deep that the light
of sun never reaches to it. As a result, the water inside the deepest parts becomes
very cold around 1.1 degree C (34 degrees F).
Due to the abysmal depth of the place the
water pressure here is extremely high. Due to the high pressure, no light and
lack of oxygen, common sea animals cannot survive here. But there are some
special fishes and invertebrates that thrive in this ecological niche.
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