How did satellites see the eruption?

Two NASA spacecraft captured the event from orbit:

• The OLI (Operational Land Imager) on Landsat 8, a joint NASA–U.S. Geological Survey mission, recorded a bright white plume of volcanic gas rising above a darker brown ash cloud.
• The VIIRS (Visible Infrared Imaging Radiometer Suite) on the Suomi NPP satellite imaged volcanic material spreading across a much wider region.

Both instruments detect visible and infrared light coming from Earth's surface and atmosphere. Scientists use the data to track plume composition, height, and movement.

Why did airports close?

Volcanic ash is abrasive. The tiny rock fragments can fuse onto engine parts and stall jet turbines. Aviation authorities therefore keep aircraft well away from ash-rich airspace.

By September 8, the eight closed airports had resumed normal service.

How far did the ash travel?

Indonesia's Humanitarian Coordination Platform (IHCP) reported ash falling over communities east of Anak Krakatau, including Jakarta and other parts of West Java. Jakarta sits about 100 kilometers (60 miles) east of the volcano.

The IHCP also noted that volcanic ash differs from the smoke produced by Indonesian peatland fires. The two have different particle sizes, move through the atmosphere differently, and demand different protective measures.

What are the health risks?

Volcanic ash contains tiny fragments of rock, minerals, and glass. Inhaling these particles can irritate airways, eyes, and skin. People with asthma or other lung conditions face the greatest danger.

Local authorities urged residents in heavy ashfall zones to wear masks and stay indoors.

Is the volcano still dangerous?

Explosive activity weakened on September 6, though the volcano continued to rumble. Its behavior shifted back toward typical Strombolian bursts of ash and rock.

Anak Krakatau remained at the second-highest level on Indonesia's volcanic warning scale. The volcano has held that status since early July 2026.