Tame compared to other kinds of volcanoes. Hawaiian volcanoes are of the shield type. While huge there is not risk of big explosions. Lava is very fluid however and can reach far away quickly. Stratovolcanoes as Pinatubo, Mount St Helens, Teide or Vesuvius are the dangerous ones. They are the megaton sized explosions, piroclastic clouds and that sort of things type. Better to be 100km away at eruption.
The next eruption of the Thera volcano will likely erase half of the central aegean. And obviously nothing on Thera (Santorini) will remain.