According to the USGS, the Hawaiian Volcano Observatory (HVO) is observing a noteworthy earthquake swarm at the summit of the Kilauea Volcano on the Big Island of Hawaii. While the volcano isn’t erupting at this moment, that could change in the days ahead.
USGS equipment detected an increase in earthquake activity beneath the south part of Kīlauea summit caldera, within Hawaiʻi Volcanoes National Park, within the last 24 hours. The activity began around 4:30 pm HT on August 23 and continued through the night and into the early morning of August 24, 2021. At about 1:30 am this morning, the swarm of earthquakes intensified in this region and was accompanied by an increase in the rate of ground deformation recorded by the Sandhill tiltmeter, just to the west of the earthquake swarm location. “These observations may indicate a small dike intrusion of magma occurring 0.6-1.2 miles beneath the south caldera,” HVO said in an update this morning. “Over 100 earthquakes have been recorded as of 2:30 am on August 24; the largest recorded earthquake was magnitude 3.3 with the majority of earthquakes less than magnitude 1. Small earthquakes are continuing at a rate of at least 10 detected earthquakes per hour. Currently, webcams show no evidence of lava at the surface.” HVO added that their scientists will continue to monitor the situation and will issue additional messages and alert level changes as warranted by changing activity.
HVO is responsible for issuing Aviation Codes and Volcanic Activity Alert Levels. Aviation Codes are green, yellow, orange, or red. When ground-based instrumentation is insufficient to establish that a volcano is at a typical background level of activity, it is simply “unassigned.” While green means typical activity associated with a non-eruptive state, yellow means a volcano is exhibiting signs of elevated unrest above known background levels. When a volcano exhibits heightened or escalating unrest with the increased potential of eruption, it jumps to orange. Finally, when an eruption is imminent with significant emission of volcanic ash expected in the atmosphere or an eruption is underway with significant emission of volcanic ash into the atmosphere, the code becomes red. Volcanic Activity Alert levels are normal, advisory, watch, or warning. As with aviation codes, if data is insufficient, it is simply labeled as “unassigned.” When the volcano is at typical background activity in a non-eruptive state, it is considered normal. If the volcano exhibits signs of elevated unrest above background level, an advisory is issued. If a volcano exhibits heightened or escalating unrest, a watch is issued while a warning is issued when a hazardous eruption is imminent.
With this activity at Kilauea, HVO has set the volcano to a YELLOW aviation code and a WATCH volcanic activity alert level. The same is true for the nearby Mauna Loa volcano, considered to be the world’s largest active volcano.