Under the theory of science as the study of what is falsifiable, there's nothing here to falsify because there is no way to disprove that a conjectured but unobserved collision of two massive bodies was something else or didn't occur. Which is to say that it is impossible to falsify that a conjecture is a conjecture.
That there is not a geophysical theory, doesn't have a bearing on the correctness of the gravitational wave theory one way or the other...anymore than the absence of a helio-centric model for the solar system made the geocentric model more correct or the absence of a theory of oxygen made the theory of pholgiston more correct. More importantly, both these incorrect theories had reasonable explanatory power to the point that they were useful.
The reason they were useful theories is because they were predictive, pholgiston allowed a person to calculate the weight of ashes after burning and the geocentric solar model made the prediction of the location of stars possible with reasonable precision. On the other hand, theories that offer conclusions about unfalsifiable propositions are what Carnap and the Vienna circle termed "metaphysics".
The conclusion that the experiment justifies is that the Earth resonates. There is no external event to which the measurements can be correlated to establish causality. There's no confidence interval. It's a case where the observations confirm a pre-existing world view under the same human cognitive structures by which seashells on mountain tops confirm a world-wide flood. It assumes that because we live on the Earth we know everything about it.
Anyway, it's a case of over-reaching with the conclusions. It's an argument from design.