For what it's worth, the scientists at the US Geological Survey who study Kīlauea do not agree with the Nature paper:
https://volcanoes.usgs.gov/observatories/hvo/hvo_volcano_wat...
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Our analysis indicates that increasing pressure in the magmatic system, which far exceeds the change in pressure modeled as due to rainwater infiltration, was the primary driver in triggering the 2018 eruption.
For HVO, the smoking gun is found in the ground deformation record across a broad region of Kīlauea Volcano leading up to the eruption.
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In summary, our consensus interpretation of HVO's monitoring data is that magma pressurization was the driving force in triggering the events of late April and early May of 2018.
No external process, such as rainfall, is needed to explain this.
But what about the rainfall hypothesis? While the role of groundwater and rain infiltration impacting the behavior of the volcano remains an interesting area of research, we know that extreme rainfall events have occurred many times in the recent past when no eruptions occurred, and the spring 2018 rains were no greater than many previous rainstorms.
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