On January 7, 2014, NASA's Aqua satellite passed over Vanuatu, allowing the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard to capture this true-color image.
A broad plume of volcanic vog and ash rises from Ambrym and spreads across the South Pacific. Vog is a combination of “volcanic” and “smog,” and is formed when gases from a volcano react with sunlight, oxygen and moisture.
The vog appears as a light blue-gray plume which arcs from the volcanic island both to the northwest and to the northeast. In the northeast, the vog crosses a mirror-like swath of silver-gray which runs from north to south. That swath is not volcanic in origin, but is an artifact called “sunglint” — the reflection of the sun off the ocean in a satellite image.