We’re on Bunter sandstone, which I think is classed as alluvial. Although we are a fair way from the epicentre, so even if I’d been awake I doubt I’d have felt it.
Alluvial 250m years ago, but now consolidated into hard stone, witness its use in building and cliff formation.. The alluvial strata which respond to earthquake vibrations are recent deposits, as in fens, river valleys, drained lake bedsetc.
Everyone talks about the weather but no-one does anything about it - Mark Twain
Chichester 12m asl