2018 Fiji earthquake

The Fiji earthquakes of 2018 occurred on August 19, 2018, at 00:19:40 UTC. Its epicenter was located close to the Fijian island Lakeba, and about 270 km from the small town of Levuka on Ovalau. The earthquake registered a magnitude of 8.2 and is the largest earthquake of 2018. The earthquake had a focal depth of 600 km, making it the second largest earthquake ever recorded at a depth greater than 300 km, a tie with the 1994 Bolivia earthquake, and behind the 2013 Sea of Okhotsk earthquake. Earthquakes are common in the region as the Pacific Plate is still seismically active under the Fijian Islands, even after subduction along the Kermadec–Tonga Trench. An 7.9 event would hit the islands again on September 6 the same year, this time at a depth of 670 km, this earthquake was a mainshock of its own. Both earthquakes may be considered a doublet event.
Earthquake.
"see Deep-focus earthquake and Wadati-Benioff zone"
Deep earthquakes are commonly defined as events occurring at a depth of 300 km or greater. These earthquakes occur within subducting slabs that are descending into the mantle. As these plates bend or flex, faults break out to accommodate the deformation and along with it, occasionally producing earthquakes.
August 19.
Initially reported as an 8.0 earthquake, it was later revised by the United States Geological Survey to an 8.2. Due to the earthquake being a deep-focus event, no damage was reported but it was widely felt. Small "tsunami" waves were also spotted along the coast, although it was too deep to generate any negligible tsunami. More than 250 aftershocks were seen 34 days after the main event. Focal mechanism solution suggest the earthquake had a complex rupture process and fast rupture velocity of 4.1 km/s. Rupture was observed along multiple faults in a mainly north northeast striking plane for a suggested length of 102 to 152 km.
September 6.
Eighteen days after the 8.2 event, another earthquake struck closer to the island of Viti Levu. The 7.9 earthquake was a downgrade from an initial magnitude of 8.1. The earthquake had a complex combination of strike-slip and dip-slip during rupture within the slab. It was an unusual event the portion of the slab is rather aseismic. The depth of this event was slightly deeper than the first quake, and the rupture velocity was much slower, at 2.5 km/s. It was suggested that coulomb stress transfer from the 8.2 quake may have triggered the 7.9 earthquake however, stress from the first quake was not sufficient to generate the next event alone. The 7.9 event may have been dynamically triggered by the 8.2 quake but the 18-day interval period was longer than usual as triggered quakes usually nucleate within a few hours to days.