There are some biological preps/tank arrangement schemes for earthquakes (same preps as storm/power outage regions) that can be customized uniquely for these risks vs other areas that don't have as many challenges, and they make a big deal on life vs death/non hardware related planning.
cascading loss of a billion former aerobes is the catalyst to recycling in stressed out systems/stilled ones/quaked ones
if the hardware survives, the way the tank is designed regarding organic retention determines your oxygen demand, the next weakest link in the chain of life within those walls. biological oxygen demand is a big deal, determines lifespan during the event and the trend today is packing in surface area, in sumps and in the external filters and in tank, which instantly reverses into a liability the minute the system stills outside of design.
in any form of stilled/power outage and especially for jostling and rock stack falling, you want the lowest amount of stored organics you can have. detritus is half rotten proteins in various stages of decomp... that's why old threads on sandbed access / doing things partially / upwells a bunch of mid level ammonia and things died. Nowadays we're thorough, whole-bed-at-once type cleaning, or we go bare bottom all at once (no ramp down required) cloudless, and no tanks ever die. you want to be shaking clean sand vs awesome old sand that denitrifies its own waste.
This is the weight of detritus figuratively speaking in an enclosed system...the tax that mass commands.
The heterotrophic bacteria that colonize detritus are aerobes, by the millions, and Ill bet anyone with enough click time might establish that a 200 gallon aquarium with the usual 1998 sandbed setup has a surface area + organic substrate factor that commands more oxygen than the whole fish bioload added up and doubled. It'd be worth a click to evaluate the claim-> its mighty close Ill bet. it means if you have a clean tank and the power goes out, your fish bioload becomes the greatest oxygen demand and there are ways to mitigate that creatively vs a 3x load where its fish, your awesome remote DSB, a refugium etc all outputting co2 and commanding oxygen at a massive rate.
The safest continual aquarium design for a challenge-prone reef aquarium is just enough surface area to run your needed bioload stand alone (minimal live rock, bare bottom is ideal) and as little detritus clouding as you are willing to store up day to day.
