Ocean Trenches

Dive into the trenches...

HADAL ZONE!

Most ocean trenches circle the Pacific in the "Ring of Fire," which also includes active volcanoes and earthquake zones. ​

​How do ocean trenches form?

​

​How do ocean trenches form?

​Ocean trenches are a result of the process of subduction, where dense oceanic crust slides beneath less-dense crust. The red arrow indicates the subduction zone forming the massive Mariana Trench.

In summary . . .

• ​Oceanic trenches occur in oceans throughout the world

• Only make up a small portion of sea floor

• Form at converging plate boundaries because of subduction zones

• Most in Pacific Ocean along the "Ring of Fire"

Mariana Trench

• 1554 miles long

• 44 miles wide

• Deepest Point- Challenger Deep 35, 814 feet (7 miles)

​The Challenger Deep

​Mt. Everest underwater!

​Diving into the deep . . .

First Dive!

• Trieste

• January 23, 1960

• Jacques Piccard (2008) & Don Walsh

• They reached the bottom at a depth of 10,916 meters (35,814 ft).

• Took 4 hours 43 mins to reach bottom

• ​Ascent took 3 hours and 15 minutes.

Findings?

• Described the sea bottom as a “diatomaceous ooze.”

• Only stayed 20 minutes and did not take any pictures because of the silt that was stirred up.

• Thought they saw what looked like flat fish

Multiple Choice

How is the subduction zone formed?

• When two plates slide each past each other

• When two plates move away from each other

• When two plates move toward each other

• When one tectonic plate sinks below another

Multiple Choice

What happens at the boundary where a continental plate and an oceanic plate collide?

• The two plates are moving

• Mountains develop on edge of the oceanic plate

• The continental plate slips under the oceanic plate

• The oceanic plate is forced down under the continental plate

Multiple Choice

Why does the oceanic crust sink beneath the continental crust at a subduction boundary?

• The oceanic crust is hotter

• The oceanic crust has a greater density

• The oceanic crust has a lighter density

• The oceanic crust has more magnetic composition

Multiple Choice

This trench is located in the western Pacific Ocean and it was said to be the deepest natural trench in the world.

• Philippine Trench

• Mariana Trench

• Pacific Trench

• Atlantic Trench

Multiple Choice

How deep is the Mariana Trench?

• 3 miles

• 7 miles

• 11 miles

• 27 miles

Multiple Choice

What is the name of the vessel that Don Walsh and Jacques Piccard used to descend to the Challenger Deep?

• The Beagle

• USS Constitution

• Trieste

• Rolex

Multiple Choice

How long did Don Walsh and Jacques Piccard remain at the bottom of the Challenger Deep?

• 20 seconds

• 20 minutes

• 20 hours

• 20 days

Second Dive

Deepsea Challenger

March 26, 2012

James Cameron

10,908 meters (35,787 feet)

took 2 hours 37 mins to reach bottom

​The Deepsea Challenger

​

Findings?

• On March 26, 2012, more than 52 years after the Trieste's dive into the Challenger Deep, Cameron plunged 10,908 meters (35,787 feet, 11 kilometers, 6.8 miles) below the ocean surface and became the first solo diver to reach such depths.

• Two hour and 36 minute descent​

• Traveled along the bottom for about 3 hours

• ​Reported it being a flat plain with a soft, gelatinous sea floor

​

Where is Deep Sea Challenger today?

• Donated to Woods Hole Oceanographic Institution in Massachusetts in 2013

• In 2015 the Australian National Maritime Museum (ANMM) wanted a "turn" for display

• Sadly in transit to Baltimore in July 2015, the truck had issues with brakes and tire blowout causing massive damage

• Now being repaired in U.S.

• ​Retired from diving

Third Dive

• In 2015, businessman and explorer Victor Vescovo partnered with Triton Submarines LLC to design and build the Limiting Factor to enable Vescovo to conduct the Five Deeps Expedition to visit the deepest points in the world's five oceans.

​Five Deeps Expedition

​The Limiting Factor

Findings?

• Vescovo and his team completed five dives into the Challenger Deep over 8 days.

• Dive 1 occurred on April 28, 2019.

• Deepest dive of the mission and in human history

• Vescovo reached the bottom at a depth of 10,925 meters +/- 6.5 m (35,843 ft +/- 21 ft) (10.92 km, 6.79 miles)

• ​Time on bottom was 248 minutes

• Regular Styrofoam cups, after they have been to the Challenger Deep. The 16,000 psi at the bottom shrinks the cups to about ½ or less of their regular size.The crew regularly hand-drew designs on cups and put them in a mesh bag outside the Limiting Factor pressure hull. Here are two of mine

What's Victor done since May 2019?

• Went back to Marian Trench in 2020

• Took 6 passengers over the course of 6 dives

• Kathy Sullivan- First Woman to go to the deep

• Kelly Walsh- Son of Don Walsh

• By the end of 2020, he had done 8 dives!

Multiple Choice

What is the name of Victor Vescovo's submersible?

• Trieste

• Deepsea Challnger

• DSV Limiting Factor

• Vescovo Sub

Multiple Choice

How many miles deep is the Mariana Trench

• 2

• 5

• 7

• 9

Multiple Choice

How long did the first submersible stay at the bottom of the Mariana Trench?

• 3 hours

• 20 minutes

• 4 hours

• 1 hour

Multiple Choice

Who was in the sub in 2019?

• Don Walsh

• James Cameron

• Victor Vescovo

• Kathy Sullivan

Multiple Choice

Where is a trench usually located?

• Converging plate boundary

• diverging plate boundary

• hydrothermal vents

• hot geysers

Multiple Choice

What is the name of deepest known species of fish called?

• small fish

• snail fish

• amphipod

• JIM fish

Multiple Choice

What year did the first successful mission into the Mariana Trench take place?

• 1906

• 1960

• 2012

• 2019

Multiple Choice

How many people does “James Cameron’s” sub hold?

• 1

• 2

• 3

• 4

Multiple Choice

How many pictures were taken of the first successful mission to the bottom of the Mariana Trench?

• 0

• 2

• dozens

• hundreds

Multiple Choice

What zone is the Mariana

trench located in?

• photic zone

• pelagic zone

• abyssal zone

• hadal zone