【大学受験対策】英語長文問題67（地震と火山）358語＋和訳・解答解説

Earthquakes and volcanic eruptions are among the most powerful natural events on Earth. Both are caused by movements deep beneath the planet’s surface, where tectonic plates shift and collide. While these phenomena are often linked, understanding their relationship—and predicting when they will occur—remains one of the greatest challenges in earth science.

Volcanoes and earthquakes originate from similar geological processes. Magma rising through the Earth’s crust can trigger both volcanic eruptions and seismic activity. In fact, earthquakes often occur before or during eruptions, serving as one of the key warning signs that a volcano might soon become active. For example, in the weeks leading up to the 1980 eruption of Mount St. Helens in the United States, scientists recorded thousands of small tremors and a noticeable bulge on the mountain’s surface. These signals allowed for partial evacuations, saving many lives.

Despite such successes, predicting earthquakes remains far more difficult than forecasting volcanic eruptions. Earthquakes can strike without warning, even in regions with advanced monitoring systems. Unlike volcanoes, which show physical signs like gas emissions or ground swelling, earthquakes offer fewer clues. Scientists rely on data from seismographs, GPS sensors, and satellite imagery, but even with this technology, most predictions are limited to identifying long-term risk zones rather than exact times or locations.

In recent years, research has focused on patterns of “earthquake swarms”—a series of small quakes that may precede a larger one. While promising, this approach still lacks the precision needed for short-term forecasting. Similarly, artificial intelligence and machine learning models are being developed to detect subtle changes in underground stress levels, but these tools are still in the experimental stage.

Ultimately, while complete prediction may be out of reach, early warning systems and public education remain essential. Countries like Japan and Chile, which experience frequent seismic activity, have implemented real-time alert systems that can shut down trains and warn citizens seconds before a quake hits. Though brief, these warnings can make a significant difference.

Volcanic and seismic forecasting continues to evolve, combining geological insight, technological advancement, and international cooperation. Though nature remains unpredictable, each step forward brings us closer to understanding—and living more safely with—our dynamic planet.

Q1. What major difficulty regarding volcanoes and earthquakes does the passage emphasize?

1. Determining their exact chemical composition requires extensive laboratory experiments.
2. Predicting the precise timing of events remains extremely difficult.
3. Calculating total energy released during eruptions has become universally straightforward.
4. Mapping every tectonic boundary worldwide has been completed without controversy.

Q2. Why is forecasting earthquakes considered harder than predicting volcanic eruptions?

1. Because eruptions generate fewer economic losses than major seismic disasters.
2. Because volcanoes often erupt underwater, making measurements extremely expensive.
3. Because satellites cannot detect surface changes associated with magma movement.
4. Because earthquakes provide fewer physical warning signs than active volcanoes do.

Q3. Which of the following statements is NOT mentioned in the passage?

1. Small tremors can precede eruptions, offering valuable evacuation warnings.
2. Scientists study quake swarms hoping to improve short‑term forecasts.
3. Real‑time alerts can pause trains seconds before shaking arrives.
4. Deep‑sea drilling routinely triggers significant quakes near tectonic boundaries.