The mariana trench?

Question

Regarding the Mariana’s trench, this area is so deep because it is a

a. subduction zone
b. rift valley
c. abyssal plain
d. transform boundary

Answer 1

Where, and What is the Mariana Trench?

The Mariana Trench is located in the Pacific Ocean, just east of the 14 Mariana Islands (11"21' North latitude and 142" 12' East longitude ) near Japan. As you probably already know, it is the deepest part of the earth's oceans, and the deepest location of the earth itself. It was created by ocean-to-ocean subduction, a phenomena in which a plate topped by oceanic crust is subducted beneath another plate topped by oceanic crust.

answer - "a"

Answer 2

The Mariana Trench (or Marianas Trench) is the deepest known submarine trench (maximum depth of 10.9 km, 6.77 mi), and the deepest location in the Earth's crust itself. It is located in the floor of the western North Pacific Ocean, to the east and south of the Mariana Islands at , near Guam.
Description
The trench is the boundary where two tectonic plates meet, where the Pacific Plate is being subducted under the Philippine Plate. The bottom of the trench is farther below sea level than Mount Everest is above it. The trench has a maximum depth of 10,911 meters below sea level. This puts it at 6,366,400 meters from the center of the Earth. The Arctic Ocean, on the other hand, is only about 4,500 meters deep, but 6,353,000 meters from the Earth's center, some 13 kilometers closer. This is due to the equatorial bulge.
Exploration
The trench was first surveyed in 1951 by the Royal Navy vessel Challenger, which gave its name to the deepest part of the trench, the Challenger Deep. Using echo sounding, the Challenger II measured a depth of 5,960 fathoms (10,900 m, 35,760 ft) at . This sounding was repeatedly made using earphones to hear the return of the signal as the stylus passed across the graduated depth scale, whilst the timing of the speed of the echo-sounding machine, a necessary part of the process, was made with a handheld stopwatch. For these reasons it was considered prudent to subtract one scale division (of 20 fathoms) when officially reporting a new greatest depth of 5,940 fathoms (10,863 m).

In 1957, the Soviet vessel Vityaz reported a depth of 11,034 meters (36,200 ft), dubbed the Mariana Hollow. In 1962, the M.V. Spencer F. Baird recorded a greatest depth of 10,915 meters (35,810 ft). In 1984, the Japanese sent the Takuyō (拓洋), a highly specialized survey vessel out to the Mariana Trench and collected data using a narrow, multi-beam echo sounder; they reported a maximum depth of 10,924 metres (this is also reported as 10,920±10 meters). The most accurate measurement on record was taken by another Japanese probe, Kaikō (かいこう), on March 24, 1995: 10,911 meters (35,798 ft).

In an unprecedented dive, the United States Navy bathyscaphe Trieste reached the bottom at 1:06 p.m. on January 23, 1960, with U.S. Navy Lieutenant Don Walsh and Jacques Piccard on board. Iron shot was used for ballast, with gasoline for buoyancy. The onboard systems indicated a depth of 11,521 meters (37,799 ft), but this was later revised to 10,916 meters (35,813 ft). At the bottom, Walsh and Piccard were surprised to discover soles or flounder about 30 cm (1 ft) long, as well as shrimp. According to Piccard, "The bottom appeared light and clear, a waste of firm diatomaceous ooze".

At the bottom of the Mariana Trench, water exerts a pressure of 1,086 bar (108.6 MPa or 15,751 psi), over 1,000 times the standard atmospheric pressure at sea level.



ans.: A. subduction zone

Answer 3

I agree with Doug. "A"