![]() Slow lava effusion fed the growing dome and flows that advanced down the Mi-Isi (S) and Bonga (SE) drainages. Average daily measurements of sulfur dioxide emissions fluctuated between 595 and 1,002 tonnes per day. Daily steam-and-gas emissions rose as high as 2.5 km above the crater and drifted multiple directions. PHIVOLCS reported that eruptive activity continued at Mayon during 27 June-4 July. By 1424 on 4 July the lava flow was about 3.5 km long based on satellite image analysis. During 3-4 July the lava emission rate fluctuated between 5 and 20 m/s based on satellite data, and the flow front advanced at a rate of about 40 meters per hour based on webcam images. A sharp decline in volcanic tremor amplitude was noted at 1012 and remained at lower levels. The lava flows continued to advance, reaching 650 m elevation, in an area about 2.4 km from the nearest road. Active lava fountaining was building several cones along the SE-flank fissure. The lava flows from those fissures had stopped at around 1,700 m elevation. Field teams made visual observations during 0800-1000 on 3 July and noted that the E-flank fissures were no longer active, producing only gas emissions. In general, the lava emission rate fluctuated between 7 and 27 meters per second (m/s), averaging 12 m/s, based on satellite data. The fissure was about 500 m long, trended NNW-SSE, and produced lava flows that traveled E.īy 0430 on 3 July the SE flank fissure was the most active of the two fissure areas, with lava flows traveling longer distances to the E than from the higher E-flank fissures. Tremor was variable and again increased a fourth fissure opened at around 1750 at the top of the Grandes Pentes on the SE flank, around 1,500 m elevation. Tremor decreased sharply and during 1145-1230 no surface activity was visible. Lava from the two at the higher elevation traveled ENE and lava from the third fissure traveled E. Two fissures were near each other, and one was located to the NE all three trended NE-SW. An overflight was conducted, and three fissures were located at an elevation of about 2,000 m in an area N of Piton Vouvoul. OVPF recommended a change in the Alert Level to 2-1, the lowest of two sub-levels in “Alert 2: ongoing eruption” (inside the Enclos Fouqué caldera) Alert 2 is the third level on a four-color eruption scale. Volcanic tremor began at 0830, signifying the arrival of magma at the surface, and fissures opened on the E flank. OVPF reported that a seismic crisis at Piton de la Fournaise began at 0736 on 2 July and was accompanied by rapid deformation. Complete updates are done about every 6-8 weeks, but information about newer eruptions can be found in the Weekly Report. ![]() An eruption listed here might have ended since the last data update, or at the update time a firm end date had not yet been determined due to potential renewed activity. The most recently started eruption is at the top, continuing as of the Stop Date given. The Smithsonian / USGS Weekly Volcanic Activity Report (WVAR) for the week ending on 4 July 2023 includes the 23 volcanoes shown below marked "Yes" in the WVAR column (rollover for report). Additional annual eruption data is available for recent years. There are typically 40-50 continuing eruptions, and out of those generally around 20 will be actively erupting on any particular day (though we do not keep detailed statistics on daily activity). An eruption marked as "continuing" does not always mean persistent daily activity, but indicates at least intermittent eruptive events without a break of 3 months or more. Overall, 48 volcanoes were in continuing eruption status as of 9 June 2023.
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