I'm not sure where the anomaly map versus gravity map angle comes from? In essence, it's one in the same.
Not one and the same.
Gravity anomaly = observed acceleration – theoretical acceleration due to gravity
The terms on the right are two large numbers. Let’s say 982,972,760.4 for observed acceleration, 982,972,175.1 for theoretical acceleration. But the difference is a small number (585.3). So not the same in any sense.
To get the discussion back on track we need to focus on observed acceleration, which differs across the globe. It’s about 5 million higher at the poles than at the equator.
Tom is having difficulty with this idea, hence our long detour through the rabbit hole of ‘anomaly’.
And so I take it that [Tom’s] whole angle here is that seismometer measurements and gravity meter measurements are simply one in the same and those who measure gravity variances/anomalies are actually just mistaking such for seismic activity?
That is Tom’s belief, as I understand it. It strikes me as preposterous for a number of reasons. For example, gravimeters are highly sensitive instruments and will be disturbed by the tiniest movement, so you would not make observations during seismic activity.