The Tohoku earthquake of March 2011 was magnitude 9 on the Richter scale  and about as bad as an earthquake can get. It was powerful enough to shift part of Japan measurably closer to America, to alter the axis around which the mass of the planet is balanced and to shave more than a microsecond off the length of the day. It sent destructive seismic waves racing around the world  and ominously towards Honshu  at speeds of 7,000km/h and more, and it generated a tsunami. The earthquake itself killed 230 people.

That so few died is a tribute to Japanese builders, planners and the education system. Seismic waves travel at rocket speeds but information travels at the speed of light, and seconds before the first waves arrived to damage bridges, trigger landslides and buckle the rail track in at least 1,200 places, Japanese Railways had shut down its bullet train network.

Lives were saved because a nation was ready and its citizens knew what to expect. But the tsunami that swept in from the earthquake's epicentre 20 minutes later, and washed away most of a small fishing port and swamped the Fukushima Daiichi nuclear plant, killed at least 15,000. Many of those lives were lost because, although people of the coast knew a lot about tsunamis, nobody expected a wave that high and a mass of water that destructive. The breakwaters were overwhelmed and the "blue line"  the marker for altitude above which people should be safe  was too low. There were warnings, but many missed them and others who thought they were safe stayed put.

The lesson is that there may be a limit to an earthquake's force, but not to its destructive potential. In an earthquake, people die because they are in the hazard zone, because they do not know what to expect, because they have not been warned in time and most of all because their civic government is corrupt and their buildings are unsafe.

In January 2010, a magnitude 7 earthquake hit Port-au-Prince, Haiti's capital. Magnitude 7 is 100 times smaller than magnitude 9. But the Haiti earthquake, with an official estimate of 316,000 deaths, is the second most destructive in recorded human history. According to the US Geological Survey, 97,294 houses were destroyed and more than 188,000 damaged. A month later, a magnitude 8.8 earthquake ripped along 700km of the coast of Chile, and shifted parts of the Earth's crust by as much as 10 metres. It was one of the most violent earthquakes in history and it claimed 521 lives.

Chile is not  compared with Japan, California or New Zealand  a wealthy country. But its citizens knew what to expect, and its houses were built to survive. Haiti is one of the world's poorest countries, with a notorious experience of appalling government, and its poorest people were crammed into unsafe buildings on unstable ground. The ones who died in the first minutes could not even have known what hit them.

Twelve of the world's 15 largest cities are in the developing world. One day, seismic waves are going to race through a city that has doubled in size in the last 30 years  a magalopolis where the landlords are greedy and the building inspectors can be bought off with a bribe  and more than a million people will perish. And it will happen not because earthquakes are more frequent, but because the planet's population is growing at 80 million a year, mostly in the cities of the developing world, and those most at risk are the 2 billion or so scraping by on less than $2 a day. The hazard is the same, but the number of potential victims has grown threefold in one lifetime. The Million Death Quake is a good book in a number of ways: people with no background in Earth sciences can understand every word of it; its author is the head of seismic hazard for the British Geological Survey and writes with authority; he has spent most of his career explaining earthquakes to journalists and broadcasters; and, above all, it could help save lives.

Earthquakes are a fact of life: potentially calamitous, but inevitable, even necessary, symptoms of the subterranean pulse that permits life in the first place. Desert cities begin along earthquake faults because the same ruptures also release natural springs of water; Wellington in New Zealand has grown up around a beautiful harbour shaped by a calamitous earthquake in 1855.

Earthquakes are not a punishment from God, which was the favoured explanation up to and even beyond the Lisbon earthquake of 1755. They may be inevitable but they are not predictable, in the sense that you could hope to warn people to leave this or that town, on such a day. And, despite the astonishing advances in Earth science over the last five decades, they are still quite difficult to describe. Thales of Miletus, Aristotle and Seneca all tried to make sense of them; so did the chemist Robert Boyle, the astronomer John Flamsteed and the philosopher Immanuel Kant. It wasn't until the San Francisco earthquake of 1906 that researchers began to piece together the mysterious subterranean machinery of destruction.

Musson tells the whole story conversationally, but missing nothing that matters  the compression, shear and surface waves that bounce buildings up and down and then shake them from side to side; the ground acceleration that can exceed gravitational forces and send rocks and people flying upwards; the astonishing strains along fault zones that can be suddenly released at any time, to unleash stupefying quantities of energy, and the reasons why buildings fall down, even in California.

At the conclusion, you will know not to ask about the Richter scale, and understand that magnitude is only one measure of an earthquake, and not always a helpful one at that. You will know seismic research has shaped our understanding not just of the globe's surface, but its structure at depth. Most of all, you will understand that earthquakes don't kill people  their offices, factories, tenements and houses do. There could hardly be a more serious take-home message.

 Tim Radford served on the UK committee of the UN International Decade for Natural Disaster Reduction.