I was in Hawaii 2 weeks ago on vacation (my sister and nephew lives in Maui and I never visited them there......went down to the coast in Volcanos national park in daytime....saw the steam cloud...and a spot or 2 of orange...from a surface flow on the pali (fault scarp), and in the steam cloud. 16 years ago, the National park prevented anyone from walking out on the recent lava...so everyone went infrom the other, private side and just walked right out in their sandals. To their credit, the NPS now encourages people to walk on hot lava (hey, they got the entry fee...and they don't take an exit fee, so why not). They have a rope to keep you out of right by the ocean where shelf collapses occur and have been fatal. But, that rope line goes right across where the western lava tubes are dumping into the ocean. We got to where the rock was very much on the hot side...made my daughter nervous..I went farther, but I was nervous. The next day, we hiked up to the free cabin at 3000 m....that is one of the most deceptively hard hikes you can do....the grade is gentle, and it is only 7.5 miles.....but it took 7 hours for us...it is hard to walk on lava, and the elevation slows you down. I want to get to the cabin near the summit someday...but it is another 1000 m, and 11.5 miles (like the mixing of units?)....and at 3000 m, even with winter clothes and decent sleeping bag, it was just flat out cold (there was still a LOT of snow higher up...especially on N and E facing slopes on Muona Loa and Kea...).
Next day, we hiked back down, and near sunset, went back to the lava. As the sunset, and then the full moon rose, the surface lava flow lit up. The entry at the sea was pretty spectacular...as was the larger, more distant one. there were 100s of tourists...sneakers, babies, etc...hiking on rough lava 2 miles each way with flashlights. We got back to where the rock started getting a bit hot and the air was getting rather warm....so my daughter did not want to go on...even though some people said you just had to go over there a couple 100 meters to stand right next to the red hot lava...I was going to do it, but decided to save it for my next trip in another 16 years, when Kilauia (sp?) will still be pumping away. Some of the people had hiked out 5 miles to the larger flow...on our hike up Mauna Loa we walked for a while with a day hiker who said the best way to get to the active Pu Oo (sp?) vent......you can peer right in....but I guess the last mile is a little hairy....we did not have time to do that, and the coastal option was right for us....
The basal fault beneath that coastal area at 10 km depth is one of the fastest in the world....10 cm (100 mm)/yr. There was a M7.5 earthquake in 1975 that unleashed a local tsunami that caught a dozen or so people at the NPS campground and killed 2 of them. When I was there in 1989 we were camping, but that campground gave me the heebie-jeebies so we stayed at 1000 m elevation. The campground (and the park service headquarters near there) do not exist now...covered in lava. Geologic time on this coast occurs as you watch it. But, no, even at these high rates you can't make such an enormous mountain as Mauna Loa in 10,000 years
Chris