The Sanfransico earthquake happens at 5:12 am at April 18 1906. The length. The earthquake was 296 miles long and lasted 45-60 seconds. It was so strong that you could feel it in Oregon! Here is an example of what the earthquake was like:
Seismographs are used to study earthquakes. They are used to study the highest of movements in the earth seismologist do that. The first seismoscope was mad in 1751 and not until 1855 as a source of earthquakes.
Some people lost there lives about 500 years people had been getting killed by earthquakes about over 240,000 in 1976 in Tang-Shan. One thing that really makes us sad is that you can pay for structure but you can never pay for family members lost lives.