1. Case Study : Mariana Trench
About Mariana Trench :
Location :
The Mariana Trench is the deepest point on Earth. The Mariana Trench is a crescent-
The Mariana Trench is located in the
shaped scar in the Earth’s crust that measures more than 1, 500 miles (2, 550
western Pacific east of the Philippines
kilometers) long of approximately 124
and an average and 43 miles (69 kilometers) wide on average. The distance between
the surface kilometers) east of the
miles (200 of the ocean and the trench’s deepest point – the Challenger Deep, which
lies aboutIslands.
Mariana 200 miles (322 kilometers) southwest of the U.S. territory of Guam – is
nearly 7 miles (11 kilometers). The pressure at the deepest part of Mariana Trench is
over 8 tons per square inch.
Formation of Mariana Trench :
1) The oceanic crust, the Philippine
Plate, is much heavier than the
continental crust, the Eurasian
Plate.
2) When these plates collide into
each other, the Philippine Plate,
which is much denser and heavier,
sinks into the molten mantle, while
the lighter, Eurasian Plate rides
up over the top.
3) The forces driving the two plates
together are really intense, so the
subducted oceanic plate creates a
trench where it drags the edge of
the edge of the continental crust
down as it descends underneath.

2. Uses of Mariana Trench
Mariana Trench is proposed as a site for nuclear waste disposal, in the hope that
tectonic plate subduction occurring at the site might eventually push the nuclear
waste deep into the Earth’s mantle. However, ocean dumping of nuclear waste is
prohibited by international law. Furthermore, plate subduction zones are associated
with very large mega thrust earthquakes, the effects of which are unpredictable and
possibly adverse to the safety of long-term disposal.
The Mariana Trench is often used as a North-South passage by submarines as it is
part of a long system of trenches that circle the Pacific Ocean, connected with the
Japan and Kuril Trenches.
Trenches are becoming much more focused in the scientific community. Geologists now
think these seismically active zones could play a central role in some earthquakes.