Which of the following ocean trenches are not located in the Pacific Ocean? 1. Bonin Trench 2. Cayman Trench 3. Kermadec Trench 4. South Sandwich Trench Select the answer using the code given below.

Correct — D, 2 and 4. Read the stem carefully — it asks which are NOT in the Pacific. The Cayman Trench lies in the Caribbean Sea between Cuba and Jamaica, on the boundary between the North American and Caribbean plates, and the Caribbean belongs to the Atlantic. The South Sandwich Trench lies east of the South Sandwich Islands in the far South Atlantic, where the South American plate goes down beneath the small Sandwich plate. Both of the others are Pacific: the Bonin or Izu-Ogasawara Trench runs south of Japan as part of the Izu-Bonin-Mariana subduction system, and the Kermadec Trench runs northeast from New Zealand towards Tonga in the South Pacific. So the two non-Pacific trenches are numbers 2 and 4.

• (a)1 and 2 — Cayman qualifies but Bonin does not. The Bonin Trench is part of the Izu-Bonin-Mariana arc south of Japan, squarely in the western Pacific.
• (b)1 and 3 — Names the two trenches that ARE in the Pacific — the exact inversion of the question. Both Bonin and Kermadec belong to Pacific subduction systems.
• (c)2 and 3 — Cayman is right, but Kermadec is Pacific, lying northeast of New Zealand and continuing into the Tonga Trench.

Ocean trenches mark subduction zones, where one plate bends down beneath another, and most of them ring the Pacific because that ocean is closing on almost every side — the reason its rim is also the Ring of Fire. The Atlantic has only two significant trenches, the Puerto Rico Trench in the Caribbean region and the South Sandwich Trench in the far south, and the Indian Ocean essentially one, the Sunda or Java Trench.

The scarcity of Atlantic trenches is the shortcut. If a trench list appears and you are asked which are not Pacific, the candidates are almost always Puerto Rico, Cayman, South Sandwich or Sunda; everything else — Mariana, Tonga, Kermadec, Bonin, Aleutian, Kuril, Japan, Philippine, Peru-Chile — belongs to the Pacific. The other habit worth building is reading the negation twice, since option (b) here is precisely the answer to the question without the word 'not'.

• The Cayman Trench lies in the Caribbean Sea between Cuba and Jamaica, on the North American and Caribbean plate boundary.
• The South Sandwich Trench lies in the far South Atlantic, east of the South Sandwich Islands.
• The Bonin or Izu-Ogasawara Trench is in the western Pacific, part of the Izu-Bonin-Mariana arc south of Japan.
• The Kermadec Trench runs northeast of New Zealand in the South Pacific and continues as the Tonga Trench.
• The Sunda or Java Trench is the Indian Ocean's principal trench; the Mariana Trench holds the deepest known point.

• Missing the word 'not' and picking the two Pacific trenches.
• Assuming the Caribbean is a separate ocean rather than part of the Atlantic.
• Confusing Kermadec with Cayman on the strength of the first letters.

A negatively worded location item — the pairing is easy, and the marks are lost on the word 'not'.

• practice — not a real PYQ

  The Sunda Trench, also called the Java Trench, lies in which ocean?

  • (a)Pacific Ocean
  • (b)Indian Ocean
  • (c)Atlantic Ocean
  • (d)Southern Ocean

  Answer(b) Indian Ocean — it runs off Sumatra and Java and is the deepest point of that ocean.

• practice — not a real PYQ

  The Puerto Rico Trench, the deepest point of its ocean, is located in the

  • (a)Pacific Ocean
  • (b)Indian Ocean
  • (c)Atlantic Ocean
  • (d)Arctic Ocean

  Answer(c) Atlantic Ocean — north of Puerto Rico, on the North American and Caribbean plate boundary.