That does seem to be true, but if I’m understanding the New Scientist article below correctly, it doesn’t seem to be something we particularly need to worry about: the research seems to emphasize karst landscapes, and I don’t think that’s what we’ve got in the Taipei area (but is that what they have in Kending?)
Quoting the second article below:
On non-karst land surfaces, rainfall presses down on the Earth in a relatively uniform fashion, and is generally fairly swiftly carried away by surface rivers and streams. As a result, the pressure of the rainfall on any underlying fault is small.
But in karst, rain pours into the channels and caves. It does not run off the rock but runs into it, like water running through a complex plumbing network. As a result the pressure of the rain builds up inside the “pipes”. And this, says Miller, is what is making rain trigger earthquakes.
He explains that increasing water pressure inside a rock is one of three ways to break it (squeezing and stretching the rock are the other two).
Water pressure acts like a hydraulic jack, pushing the rock apart and allowing the pieces to slide past each other. If this happens on a large scale at a fault line, it can trigger an earthquake.