A gal is a derived unit used physics and gravimetry. It is 1 cm/s^2.
Thanks.I should have been more specific in my mooching. Can you tell me if the article is saying, according to gals, there was more acceleration vertically than anticipated? The ground rose abruptly more swiftly than anticipated? I hadn’t heard of this consideration before - interesting. I would have thought Richter scale would be the calculation and then I imagined horizontal movement as a building breaker.