Of the hundreds of active volcanoes that NASA satellites have observed since the early 2000s, Kīlauea stands out. It’s one of the world’s leading emitters of thermal infrared energy, according to observations from the Aqua and Terra satellites. (Other top emitters include Bárðarbunga in Iceland and the Democratic Republic of the Congo’s Nyiragongo.)
This chart shows the volcano’s daily average spectral radiance from 2016 to 2025, underscoring its frequent activity and variability. The chart draws on data from MODVOLC, an automated volcano monitoring system developed by scientists at the University of Hawai’i. The system processes observations of all the world’s volcanoes from MODIS (Moderate Resolution Imaging Spectroradiometer) sensors and detects thermal anomalies, or “hot spots,” on a daily basis. Here, Kīlauea’s spectral radiance is shown, depicting the amount of energy emitted in a specific direction, from a specific area, at a specific wavelength.
From 2016 to 2018 (left side of the chart), Kīlauea showed low but continuous activity due to relatively gentle, long-lived eruptions at two separate vents. At Halema‘uma‘u (below), the summit crater, a previously unstable lava lake had stabilized and grown to cover about 42,000 square meters (452,000 square feet). This made it the world’s second-largest lava lake, surpassed only by Nyiragongo’s. Kīlauea’s lava lake frequently sloshed, spattered, and sometimes overflowed, sending lava across the crater floor and producing many low-level thermal anomalies.
At the same time, lava poured from Puʻu ʻŌʻō (above), a cone farther down the mountain in the East Rift—a geologically active area where eruptions are most likely. In this period, lava spilling from Puʻu ʻŌʻō sometimes formed “breakout” flows that drained all the way to the coastline and built a delta at Kamokuna as lava entered the sea.
On April 30, 2018, the situation changed abruptly. Signaling the end of Kīlauea’s longest and most voluminous known outpouring of lava in 500 years, Puʻu ʻŌʻō’s crater floor collapsed, and Puʻu ʻŌʻō stopped erupting. Magma moved through underground conduits farther east into the Lower East Rift …