For the interested lay reader, a brief, literate look at the forces that make the surface of the Earth subject to earthquakes and volcanoes.
In 1964, the great Alaskan earthquake increased the elevation of more than 180,000 square kilometers of landmass on the western coast of North America by as much as 6 meters and caused a tsunami that crossed the entire Pacific. And the May 18, 1980, eruption of Mount St. Helens triggered a pressure wave that was recorded at earthquake stations around the world. After nine terrifying hours, the summit of Mount St. Helens was missing, and a 20-kilometer-high cloud of gas, ashes, and debris darkened the area. Where an almost perfect mountain cone surrounded by forests once stood, a crater 1.5 kilometers in diameter and 1 kilometer deep was all that was left.
Even though we all know, more or less, where catastrophic earthquakes and volcanoes are likely to happen, they never fail to shock and amaze us with their destructiveness and their power to dislodge what we all take for granted: firm ground beneath our feet.
For the reader who wants a concise and accessible guide to what makes the ground shake and explode, this is the perfect introduction.