Ayone know the wattage used at a Rock concert?

In the late 60s it was fashionable to use a pile of Altec A7s driven by whatever…Altec amps maybe, Macs…and the sound was friendly and sort of warm. (My bands in the early 70s to mid 80s dragged a pair of A7s around, albeit with heavy duty bass drivers). A corner was turned in the 70s to things like JBL loaded boxes from Tycobrahe and Clair Brothers with maybe Phase Linear amps, and the new normal was REAL LOUD and somewhat less warm and friendly. I'm currently a live sound mixer for smallish shows (jazz and folkie stuff mostly) and use both powered and passive speakers that sound modern and clear, careful application of powered 18s for subs, etc., and can actually get a warmish sound…but I do miss the A7 days.

Ah yes, the A7. The band house I lived in back in ’71 had a pair of them (the bands PA, of course) in the living room as a hi-fi, powered by a Fender Showman head. Had to be careful with the volume control---the A7 was so efficient, the 65 watts of the Showman could drive them to insane SPL at the flick of a wrist. Those A7’s plus a particularly nasty Fender Twin Reverb (with a pair of JBL D120 drivers) really did some damage to my poor ears.

I could (and sometimes did) hook my trust A7s to my KLH Model 20 (the one without the tuner) compact system that had a mighty 24 watts or so per side, and it sounded great. For years we used a biamp thing made by Kustom (a non tuck and roll item) that had 200 watts for the bass bins and 100 for the horns…worked great and certainly shredded some ear balls.

yes, i used to do work for sound people here at madison squear garden and the Nassau collesium in the 70-80s. it was not unusual to run 150,000 to 400,000 back then. and i know it just kept getting bigg all the time, i used to save the smoked amps take em home and fix em. still got them tpoday. Crown was one of the biggest used, BGW, even Dynacos.Banks of amps with a few speakers each bank would be stacked and parralleled till you could run a freq sweep at 130db clean. most of this was called the pa which is nothing more than miking and distributing the bands own custom sound from local on or behind stage rack of their "rig" only the drummer didnt have his own rig and could be direct miked to the pa. this is also the system the big mixing board in the middle of the audience ran. they would almost NEVER mess with the bands rig setups. bid fistfights would result from rodies to the union arena guys. I even worked with "The Limelight" in NYC in the 80s and it had 300kw. mostly crown 10Kw 3 phase amps. i took a dew old ones and ran tig welding off the hurt outputs. at 150 amps . anyway the DI boxes are getting big but the rig is still king in the rock world.    "Sex,drugs,rock and roll"

In the early period, Metallica, played around 140db in concert.

not really, i used to carry around my spl calibrate meter and it depends on the weighting used and where you measure it. since in big venues the phase cancelling is a huge problem. the only reasonable area were the mics placed front of house near l an r of the mix board ofted used when recording the live stuff. yea they had all the individual feeds on separate tracks for later but it often went unsaved. i got a main board R to R 10" tape from Led  Nassau Colisum in 77. it had 8 tracks on a 1/2" and was a duplicate so i traded some party goodies for it. I also got a tape from the making of black and blue around 80 nassau collisium also. Ozzy even signed it. and i fell on him caus i was"sick" at the time.  you can really have fun nowadays with all the wireless Nadys and such. record your own direct feeds from the bands belt wireless transmitters. so many use similar off the shelf setups and run default freqs.
Ive heard a marshall stack in the Garden and it hardly made a peep out by the mix board, the working roadies were as loud. LOL