What does OVE stand for in earthquake engineering?

[Frederick Leuchte]

Hi everyone,

In earthquake engineering, an OVE is defined to be a very rare earthquake having a 1% chance of exceedence in 50 years (MRI = 4975 years). Does anyone know what does "OVE" stand for?

In context,
[ul]
[li]SLE-25 is a frequent earthquake having a 70% chance of exceedence in 30 years (MRI = 25 years).[/li]
[li]SLE-43 is a frequent earthquake having a 50% chance of exceedence in 30 years (MRI = 43 years).[/li]
[li]SLE-72 is an occasional earthquake having a 50% chance of exceedence in 50 years (MRI = 72 years).[/li]
[li]DBE is a rare earthquake having a 10% chance of exceedence in 50 years (MRI = 475 years).[/li]
[li]MCE is a very rare earthquake having a 2% chance of exceedence in 50 years (MRI = 2475 years).[/li]
[li]OVE is a very rare earthquake having a 1% chance of exceedence in 50 years (MRI = 4975 years).[/li]
[/ul]

I know that:
[ul]
[li]SLE stands for Service Level Earthquake[/li]
[li]DBE stands for Design Basis Earthquake[/li]
[li]MCE stands for Maximum Considered/Credible Earthquake[/li]
[/ul]

But what about OVE?

Thanks,
Frederick