May 4, 2018 Earthquake: Puna District, Hawaiian Islands, United States

Minor damage to buildings and at least 4 landslides occurred on the coast.

The May 4, 2018, Mw 6.9 earthquake in Hawai'i occurred as a result of reverse faulting on the south flank of Kilauea volcano, in the east rift zone. Preliminary focal mechanism solutions indicate rupture occurred on shallow dipping thrust fault striking southwest, or on a steeply dipping reverse fault striking southeast. This earthquake is directly associated with volcanic activity at Kilauea volcano, and the evolution of its rift system and volcanic edifice.

Seismic activity has been elevated around Kilauea volcano over the past month, punctuated over the past ~24 hours with at least 7 earthquakes of M 4.5 or larger. On May 3rd, 2018, a M 5.0 occurred nearby the M 6.9 earthquake. About an hour prior to the M 6.9 event, a M 5.4 earthquake also struck in a similar location with a similar focal mechanism solution. Since the M 6.9 earthquake, 4 aftershocks of M 4.5 or larger have been located (all in the 30 minutes following the mainshock).

Regionally, this is the largest earthquake in Hawai'i since the Ms 7.1 (USGS) / Mw 7.4 (ISC-GEM) 1975 Kalapana earthquake, which also generated a local tsunami that took 2 lives. Damage due to the 1975 earthquake and tsunami was estimated to total $4.1 million in Hawai'i. The 1975 earthquake occurred on a basal detachment fault, rather than in the shallower rift zone where recent activity has been occurring. Over the past century, 9 earthquakes of M 6 or larger have occurred around the Big Island of Hawai'i.

Pahala, HI, US - CDI: 7; Mountain View, HI, US - CDI: 6; Pepeekeo, HI, US - CDI: 6; Papaikou, HI, US - CDI: 6; Hawaii National Park, HI, US - CDI: 6

(all above from reference #13456)

A magnitude-6.9 earthquake rocked East Hawaii this afternoon, causing thousands to lose power and items to be knocked from shelves but few immediate reports of substantial damage. About 14,000 customers lost power in Hilo, Kaumana and pockets in Puna following the earthquake, Hawaii Electric Light Co. reported. At 2 p.m. the company said power was restored to about half of the customers and that crews were still working on the rest. (reference #12122)

The 4 May 2018, MW 6.9 thrust-faulting earthquake occurred a day after the first fissure eruption in Leilani Estates along the East Rift Zone of Kilauea, Hawaii, relatively early in the 2018 eruptive sequence[...]The event has a shallow-dipping thrust plane and shallow epicenter located just offshore[...]As much as 3 m of slip occurred, with the rupture having behavior similar to slow rupturing tsunami earthquakes in subduction zones, indicating a relatively weak fault.(reference #12331)