Earthquake কী?

Example 8.3 (Mount St. Helens, 1980)

In the spring of 1980, a bulge grew on the side of Mount St. Helens, as molten rock pushed up inside the mountain. On the morning of 18 May, a small earthquake shook the mountain, the bulge slid away in a giant landslide, and the volcano exploded sideways and upwards. The top 400 metres of the mountain were gone: the summit became a huge crater.

Example 8.6 (Counting on the map)

We counted the dots that lie in the shaded ring (within 500 kilometres of its middle line). Of the 1 214 volcanoes, 837 are in the ring: about 2 out of every 3. Of the 696 very large earthquakes, 532 are in the ring: about 3 out of every 4. The ring covers only a small part of the Earth, but it holds most of its volcanoes and earthquakes.