Is it an offence to land anywhere but the
nearest suitable airport?

As far as I'm aware it isn't an offense to crash anywhere other than the
nearest airport - which appears to be what you are describing.

Which authority must be notified?
Initially the US - that's where the planes crashed.
Where were the aircraft registered?


Once the
planes have landed, can they be moved from the place they stopped without
permission from the investigating authority?

Not unless they pose an immediate threat

Tony



--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE