AnnOMaly:
No, you misunderstand
No. I just don't agree.
Geologists stating that an earthquake was within the range of 780BCE to 720BCE (750BCE ± 30 years [or 785BCE to 735BCE for the later estimates of 760BCE ± 25 years]) doesn't really sound anything like 'we know Jeroboam II was around from 793BCE to 753BCE so it must have been then', because their estimates cover only part of that period, and a significantly later period. If they were merely basing their findings on the expected years of a particular reign, they would more likely have said 'early 8th century BCE'.
how do they date strata independently, scientifically, without being influenced by historical chronologies?
I don't know the specific methods of chronostratigraphy involved.