Why are telescopes on top of Mauna Kea instead of Mauna Loa?

Question

Many large and important telescopes are located on top of Mauna Kea on Hawaii. This is a great location for many reasons: it's tall enough to be above the weather, an inversion layer at night keeps the atmosphere clear and dry, etc. But right next to Mauna Kea is an equally tall mountain Mauna Loa. Although there are some instruments on Mauna Loa (a NOAA station) there aren't major telescopes. Why? What makes Mauna Kea a better location?

Answer 1

I would say it is probably because Mauna Loa is an active volcano and the practicality of travelling there is more difficult.