SONAR, satellite radar, GPS, and deep-sea diving vessels all contribute
to accurate MEASUREMENT of the depth and motion of the sea floor, and
of the motion of the continents.
Once the measurements are known, they can be analyzed to determine
whether OR NOT they support the idea of continental drift, or some other
hypothesis.
Real scientists don't go out looking for evidence to support the ideas
that they want supported. That kind of approach to research is found
more in the Flat Earth department.