This thermal image, collected on September 14, 2023, shows features of the eruption site at the summit of Kīlauea. The image looks roughly west. The brighter colors are hotter temperatures, which are closest to the several active eruptive vents on the downdropped block within the caldera. From the vents, pāhoehoe lava flows north (to the right in the image) and south (up in the image), around elevated ground from the 1982 eruption (which is the darker colored and therefore cooler material in approximately the center of the image). The area north of the eruptive vents has become perched and is at least 3 meters (15 feet) higher than the surrounding ground surface. The area of active lava has decreased from the 448 acres (181 hectares) measured on September 11 to 108 acres (44 hectares) measured on September 14. USGS image by M. Patrick. 

These thermal images look west and show the eruption at the summit Kīlauea on September 11 (the day after the eruption started) and on September 14. On September 11, multiple vents were active in a roughly east-west trending line and the area of active lava flows was approximately 448 acres (181 hectares). On September 14, only the central vents remained active and the area of active lava flows was approximately 108 acres (44 hectares). USGS images by M. Patrick. 

This telephoto view shows one of the erupting vents in Kīlauea caldera. Lava fountain heights at the vents reached up to about 10-15 meters (32-50 feet) and the horseshoe-shaped spatter ramparts that have accumulated on the south/downwind side of the vents remain 20 meters (66 feet) high. USGS photo by M. Patrick.

This telephoto view shows one of the erupting vents in Kīlauea caldera. Lava fountain heights at the vents reached up to about 10-15 meters (32-50 feet) and the horseshoe-shaped spatter ramparts that have accumulated on the south/downwind side of the vents remain 20 meters (66 feet) high. USGS photo by M. Patrick.

Much of the plume from Kīlauea’s current eruption is sulfur dioxide (SO₂). HVO’s gas monitoring station HRSDH has measured up to 12 ppm of SO₂ at its location, nearly 2 miles (3 km) southwest, downwind of the eruption. According to the International Volcanic Health Hazard Network (IVHHN), prolonged exposure to SO₂ in these concentrations is toxic. Even brief exposure to concentrations less than that will cause a respiratory response (airway resistance) and eye irritation. Concentrations more than that cause paralysis or death with extended exposure. SO₂ mixes with air as it moves away from the vent and is less of a hazard for people keeping a safe distance. While the trade winds transport plume in a southwest direction most of the time, conditions can change rapidly, especially in areas closer to the vent that remain closed to the public. USGS photo by M. Patrick. 

The plume from the current eruption rises above the floor of Halema‘uma‘u. The most recent measurements, taken September 13, indicate 20,000 tonnes per day of sulfur dioxide (SO₂) are being emitted. Vog (volcanic smog) is a visible haze comprised of gas and an aerosol of tiny particles and acidic droplets created when SO₂ and other gases emitted from a volcano chemically interact with sunlight and atmospheric oxygen, moisture, and dust. Volcanic gas emissions can pose environmental and health risks to nearby communities. USGS photo by L. Gallant. 

A view of the active fissure in Kīlauea summit caldera, with a chain of cinder cones as seen during an overflight on the afternoon of September 14, 2023. The vents within the cones are feeding lava flows that have covered nearly 500 acres (200 hectares) with new lava since the eruption began on September 10. Since then, the area of active lava has decreased to 108 acres (44 hectares) on September 14. USGS photo by L. Gallant.

A row of scones in Halema‘uma‘u are actively ejecting spatter, which helps build the height of each structure. Cone heights of 20 meters (66 feet) have been measured by field teams. Of the line of vents spanning 0.8 miles (1.4 km) that were observed active during the initial phases of the eruption, only six remain active as of September 14, 2023. USGS photo by L. Gallant. 

View of eruptive activity in Kīlauea caldera, from the west side of the caldera, looking east. The three easternmost cones, ranging from 14-20 meters (46-66 ft) fall, were far more active than the west cone in the image which was only 10 meters (33 ft) tall. There are two more weakly active vents behind this row of cones, better visible from the east side of the caldera. USGS photo by K. Lynn.

A Hawaiian Volcano Observatory geologist sets up remote cameras for a close-up view of the September 2023 eruption within Kīlauea summit caldera. These cameras will help capture changes in the eruption's behavior so that geologists studying the volcano can determine better the processes at work that create the lava fountains. USGS photo by D. Downs.

View of the eruptive vents from the east side of Kīlauea caldera, looking west-northwest toward Kīlauea Overlook. Mid-day on September 14, 2023, the cone in the foreground of the image had mild spattering within ponded lava inside the cone. USGS photo by K. Lynn.

The far eastern end of the fissure system that opened in Kīlauea caldera on September 10, 2023, was in a talus slope at the eastern end of the downdropped block. The vents associated with this part of the fissure produced weak lava fountaining that did not last long. The lava cascaded down and covers the blocks that make up the talus slope. USGS photo by D. Downs.

View from above of the fissures erupting and feeding the lava flows within Halema‘uma‘u and Kīlauea caldera. The shiny black patches are new lava flows, erupting since September 10, 2023, whereas the black dull patches tend to be spatter (molten bombs thrown out) from the vents. The vents farthest to the east have already stopped erupting molten bombs and lava. Those in the middle of the fissure system are still active with spatter being thrown as high as 65 ft (20 m) but usually less than this. USGS photo by D. Downs.

View from the ground of one of the vents erupting in Kīlauea caldera on September 14, 2023. The lava fountain heights at the vents reached up to about 10-15 meters (32-50 feet) and the horseshoe-shaped spatter ramparts that have accumulated on the south/downwind side of the vents are 20 meters (66 feet) high. USGS photo by D. Downs.