science

Sagami Trough

Sagami Trough is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sagami Trough rather than just read about it. In short: The Sagami Trough (相模トラフ, Sagami Torafu) also Sagami Trench, Sagami Megathrust, or Sagami Subduction Zone is a 340-kilometre (210 mi) long trough, which is the surface expression of the convergent plate boundary where the Philippine Sea plate is being subducted under the Okhotsk microplate. It stretches from the Boso triple junction in the east, where it meets the Japan Trench, to Sagami Bay in the west, where it me…

Key takeaways

Sagami Trough belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sagami Trough to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sagami Trough from memory before moving on to harder problems.

Reference excerpt

The Sagami Trough (相模トラフ, Sagami Torafu) also Sagami Trench, Sagami Megathrust, or Sagami Subduction Zone is a 340-kilometre (210 mi) long trough, which is the surface expression of the convergent plate boundary where the Philippine Sea plate is being subducted under the Okhotsk microplate. It stretches from the Boso triple junction in the east, where it meets the Japan Trench, to Sagami Bay in the west, where it meets the Nankai Trough. It runs north of the Izu Islands chain and the Izu–Bonin–Mariana Arc (IBM). Megathrust earthquakes associated with the Sagami Trough, known as Kantō earthquakes, are a major threat to Tokyo and the Kantō region because of the proximity to a population center (with over 36 million living in Tokyo's metro area, with a total of 43 million living in the Kanto Region) and the magnitude the Sagami Trough can create.

Earthquakes

The Sagami Trough megathrust generated the 1293 Kamakura earthquake, the 1703 Genroku earthquake, which was the greatest rupture along the trough in the last thousand years, and the 1855 (Ansei) and 1923 (Great Kanto or Taisho) earthquakes.

Illustrations

Worked examples

Example 1 — a first encounter with Sagami Trough

Start with the simplest possible case. Write down what Sagami Trough claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sagami Trough before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sagami Trough ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sagami Trough

In research: Sagami Trough appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sagami Trough in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sagami Trough is common in secondary-school and first-year university syllabi. It links to neighbouring topics Subduction zones, so understanding it makes those chapters shorter.
In everyday life: Look for Sagami Trough outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Sagami Trough in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sagami Trough means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sagami Trough out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sagami Trough in simple terms?

Why does Sagami Trough matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sagami Trough?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sagami Trough.