How do you study an earthquake that happened more than 110 years ago? With modern cutting-edge technology, applied to records made in 1906. That's when the San Francisco Earthquake killed 3,000 people and destroyed much of the city. A new science paper turned its attention on evidence from contemporary accounts, and analyzed this description of the overturned train pictured above.
At Point Reyes Station at the head of Tomales Bay the 5:15 train for San Francisco was just ready. The conductor had just swung himself on when the train gave a great lurch to the east, followed by another to the west, which threw the whole train on its side. The astonished conductor dropped off as it went over, and at the sight of the falling chimneys and breaking windows of the station, he understood that it was the Temblor. The fireman turned to jump from the engine to the west when the return shock came. He then leaped to the east and borrowing a Kodak he took a picture of the train here presented.
From this story and picture, researchers calculated that the hypocenter, the very beginning of the earthquake, must have been south of Point Reyes, California. Read how they figured this out at Gizmodo.