Hawai’i Volcano and Hurricane Hector

Hawaii Island poses natural hazards of many sorts. Since May 2018, of course the main event has been the eruption of Kilauea’s east rift zone, causing many to have to leave their homes. The lava that was once propping up the Kilauea summit abruptly left and re-emerged in the east rift, where it has created more than 100 acres of new land in the ocean around Kapoho. That abrupt move caused major subsidence at the summit, with regular collapses of the Halemaumau crater causing almost daily earthquakes of the 4th magnitude. None of these were felt either in Hilo or at the summit, as they were very localized, shallow collapses rather than earthquakes in the bulk of the island. Then, on the 4th of August, it all ceased; the chart here shows tiltmeter measurements of Kilauea summit, each major uptick being one of the 4th-mag earthquakes. At the same time, the lava erupting from “Fissure 8” in Leilani Estates in the east rift zone ceased, and the new cinder cone has only a pool of lava at its center with none now heading for the ocean entry.

Tiltmeter measurements of the Kilauea summit from mid-July until the collapse activities ceased. Data from Hawaii Volcanoes Observatory. Each major uptick marks a collapse event in the crater.

The second natural hazard threatening Hawaii is hurricanes; we are now well into Hurricane season and are already up to “H” in the naming as the East Pacific has been generating quite a few significant storms. Hector came within a couple of hundred miles of the south of the island, as a major hurricane; however the effects on Hawaii itself were quite minimal and we lost only a night and a half to the resulting instability at the summit level. Hurricane season lasts until November, so we’re keeping an eye on the East Pacific.

Hurricane Hector, apparently barreling toward Hawaii on the 7th August. In fact by this time its course was almost due west and although the island was in its outskirts the effects were relatively minor.