While some of this strain is released by moderate and smaller earthquakes and by slippage without earthquakes, geologic studies indicate that the vast bulk of the strain is released through the occurrence of major earthquakes-that is, earthquakes with Richter magnitudes of 7.0 and larger and capable of widespread damage in a developed region.
"An Assessment of the Consequences and Preparations for a Catastrophic California Earthquake: Findings and Actions Taken Prepared By Federal Emergency Management Agency"
Various
Furthermore, the load could be applied to the motor gradually through automatic relief valves on the pump and in the mechanical machines by slippage as the belt was shifted from the loose to the fast pulleys.
"Elevator Systems of the Eiffel Tower, 1889"
Robert M. Vogel