20 secs
The 1988 Armenia earthquake (25,000 killed) and 1989 Loma Prieta earthquake (63 killed), both magnitude 6.9.
Santa Cruz Mountains (Loma Prieta), California1989 10 18 00:04:15 UTC (Local 10/17/1989)Magnitude 6.9Intensity IX
The March 11, 2011 earthquake was originally measured at magnitude 8.9, but later upgraded to 9.0 by both USGS and Japan scientists.
2.4*63
There was plenty of warnings that Mt. Vesuvius would erupt. That's why so many people actually escaped. There were earth tremors and small quakes for weeks before and the water sources were drying up. The smart ones read the signs and got out.
63 people died throughout northern California.
The resultant magnitude is 60.659 N and its vectorial angle is 356.6124 degrees.
The earthquake hit the towns of Accumoli, Amatrice, and Pescara del Tronto. The death count is in the seventies, but they haven't finished searching for survivors, and they could find further casualties. Over 150 people are still reported missing.
3,757 Injuries 400 Severely Hurt Approximately 42 Fatalities
The moment magnitude scale goes as low as 0.0 and any quake that released less than 63 kilojoules of energy would registrer as 0.0 on the Richter scale. Quakes with a Richter value of 2.0 or less were classified as "microquakes" and were almost never detected by human senses.
There have been a number of earthquakes that have affected San Francisco. Perhaps the most famous are the 1906 earthquake which is estimated to have resulted in 3,000 fatalities and the more recent 1989 Loma Prieta earthquake which resulted in 63 deaths.
63 cm is 63 cm long. If you would like it to be converted to another unit of measure, like 24.8 inches, please specify.