Earthquakes happen all over the world every single day, with some never felt at all and others destroying entire cities. But what does that measurement actually mean?

An earthquake rattled much of the Northeast on Friday morning, with shaking felt across the New York City metropolitan area and in communities from Baltimore and Philadelphia up through New England.

Recently, the people of the city of Kolkata witnessed the earthquake for a short time; individuals ran out of high-rise offices to the streets in panic. Thanks to the internet, we’ve all seen it.

Preface -- ch. 1. The magnitude of the problem -- ch. 2. Formative years -- ch. 3. Margaret Rose -- ch. 4. Harnessing the horses -- ch. 5. Earthquake exploration ...