HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE U.S. Geological Survey Wednesday, October 18

HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Wednesday, October 18, 2023, 9:54 AM HST (Wednesday, October 18, 2023, 19:54 UTC)

KILAUEA (VNUM #332010)
19°25’16” N 155°17’13” W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Activity Summary:  Kīlauea volcano is not erupting. The area south-southwest of Kīlauea’s summit continues to show signs of episodic unrest as the intrusive event that began in early October continues intermittently at a lower rate. The unrest is expected to continue to wax and wane with changes of input of magma in the area.  The summit of Kīlauea remains at a high level of inflation and eruptive activity is possible in the coming weeks or months. No unusual activity has been noted along Kīlauea’s East Rift Zone or the Southwest Rift Zone.

Summit Observations: Episodic unrest continues south and southwest of the summit area of Kīlauea. Overall, inflation at the summit of Kīlauea remains high and has surpassed the level seen just before the most recent eruption on September 10th.  However, the current rate of inflation in the region have diminished significantly since October 4-6.  Waxing and waning of the unrest is expected as this event continues at lower levels of unrest.

Renewed seismicity began on October 16 and continues to be recorded beneath the south end of Kīlauea caldera extending to the southwest along the trend of December 1974 vents.  The renewed activity peaked on October 17 and has been slowly decreasing since then.Over the past 24 hours, approximately 86 earthquakes were recorded in Kīlauea summit region. Most of the earthquakes from the seismic swarm south of the caldera are at depths of around 1–3 km (0.6–2 mi) below the surface.

The Uēkahuna summit tiltmeter located north of the caldera recorded remained flat over the past 24 hours. The Sand Hill tiltmeter, located just southwest of the caldera, is showing continued inflation but the inflation rate dropped significantly overnight. GPS units within the south end of the caldera and further south and west have shown little uplift of this region since October 11, when the seismicity dropped abruptly.

Sulfur dioxide (SO₂) emission rates remain low and were measured at a rate of about 100 tonnes per day on October 6.

It is unclear how long the current unrest in Kīlauea summit region will continue. At this time, it is not possible to say with certainty if this activity will lead to an eruption; the activity may remain below the ground surface. However, an eruption remains possible, most likely in Kīlauea’s summit region inside of Hawai‘i Volcanoes National Park and away from infrastructure. Similar patterns of earthquake activity and ground deformation occurred to the south of the caldera prior to the September and June 2023 eruptions in Kīlauea summit caldera (in Halemaʻumaʻu crater and on the downdropped block). Volcanic gas emissions pose the greatest hazard to areas downwind of Kīlauea’s summit.

Although unrest in Kīlauea summit region continues, there is currently no sign of an imminent eruption and increasing inflation and earthquake activity (heightened unrest) are expected to precede an eruption. During periods of heightened unrest prior to recent eruptions at Kīlauea summit, signs of imminent eruption did not appear until 1-2 hours before lava reached the surface. The summit of Kīlauea remains at a high level of inflation and eruptive activity is possible in the coming weeks or months. HVO scientists will continue to monitor Kīlauea volcano closely and will issue additional messages as warranted by changing activity.

Rift Zone Observations: No unusual activity has been noted along the East Rift Zone or Southwest Rift Zone; steady rates of ground deformation and seismicity continue along both. Measurements from continuous gas monitoring stations downwind of Puʻuʻōʻō in the middle East Rift Zone have been below detection limits for SO₂, indicating that SO₂ emissions from Puʻuʻōʻō are negligible.

Hazard Analysis: Levels of volcanic gas (sulfur dioxide and carbon dioxide) can remain locally hazardous even though Kīlauea is no longer erupting. Sulfur dioxide (SO₂) gas emissions have greatly decreased; however, local concentrations of sulfur dioxide (SO₂) or hydrogen sulfide (H₂S) may persist in downwind areas, and residents may notice odors of these gases occasionally. Significant hazards also remain around Halemaʻumaʻu from crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. For discussion of Kīlauea hazards, please see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards.

The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea volcano.