Grímsvötn volcano (Iceland), eruption warning - increased meltwater

Grímsvötn volcano on Iceland might be heating up to a new eruption. Recently, it has been observed that the amount of glacial meltwater from Grímsvötn emerging from under the thick ice cap of Vatnajökull covering the massive volcano has doubled.
While this might well be caused by heating of the volcano due to rising magma leading to a new eruption, Icelandic volcanologist say that seismicity under the volcano is still low. There are other possible caused that could explain the increase in melt water outflow, such as geomorphical changes in the drainage system allowing an increased discharge of accumulated meltwater on top of the volcano.