Eruption of the Sierra Negra volcano in the Galapagos

July 1st, 2018 |

GOES-16 False Color RGB images [click to play animation]

GOES-16 False Color RGB images [click to play animation]

GOES-16 (GOES-East) False Color Red-Green-Blue (RGB) images from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed another eruption of the Sierra Negra volcano on the Galapagos, which began late in the day on 01 July 2018. Since the volcanic plume was rich in SO2, it exhibited a cyan appearance in the RGB imagery.

As was demonstrated following the 26 June eruption, GOES-16 Low-level Water Vapor (7.3 µm) imagery (below) can also be used to initially track volcanic plumes that have high concentrations of SO2.

GOES-16 Low-level Water Vapor (7.3 µm) images [click to play animation | MP4]

GOES-16 Low-level Water Vapor (7.3 µm) images [click to play animation | MP4]

Eruption of the Sierra Negra volcano in the Galapagos

June 26th, 2018 |


GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm), Mid-level Water Vapor (6.9 µm) and Low-level Water Vapor (7.3 µm) images beginning late in the day on 26 June 2018 (below) showed that a signature of the volcanic plume was evident in the 7.3 µm imagery for several hours after it was no longer seen in the 10.3 µm or 6.9 µm imagery — this is due to the fact that the 7.3 µm spectral band is also sensitive to SO2 absorption (and this volcanic eruption produced large amounts of SO2).

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm, top), Mid-level Water Vapor (6.9 µm, middle) and Low-level Water Vapor (7.3 µm, bottom) images [click to play animation | MP4]



Lava flows continue from Kilauea’s Lower East Rift Zone

June 18th, 2018 |

NOAA-20 VIIRS Day/Night Band (0.7 µm), Shortwave Infrared I04 (3.75 µm), Shortwave Infrared M13 (4.05 µm) and Longwave Infrared (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm), Shortwave Infrared I04 (3.75 µm), Shortwave Infrared M13 (4.05 µm) and Longwave Infrared (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm), Shortwave Infrared I04 (3.75 µm), Shortwave Infrared M13 (4.05 µm) and Longwave Infrared (11.45 µm) images (above) showed signatures of the ongoing lava flows from the Lower East Rift Zone of the Kilauea volcano on the Big Island of Hawai’i at 1225 UTC (2:25 am local time) on 18 June 2018.

Note how the central ribbon of hottest lava flow (which continues its active ocean entry) saturated the I04 3.75 µm image, causing a “wrap-around” effect to display cold brightness temperatures (white pixels) — although the M13 4.05 µm band has a lower spatial resolution, it saturates at much higher temperatures, and sensed brightness temperatures in the 480 to 557 K range. The Infrared images also showed evidence of steam clouds flowing southward over the adjacent offshore waters.

A webcam image from near Kapoho (PGcam) around the time of the NOAA-20 VIIRS images is shown below. The active Fissure 8 is near the center of the image.

Webcam image from near Kapoho [click to enlarge]

Webcam image from near Kapoho [click to enlarge]

VIIRS imagery and webcam capture courtesy of William Straka (CIMSS).

Lava flow from Kilauea in Hawai’i

June 6th, 2018 |

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly plots of surface reports [click to play MP4 animation]

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly plots of surface reports [click to play MP4 animation]

The Kilauea volcano on the Big Island of Hawai’i continued to be active into early June 2018 — and GOES-15 (GOES-West) Shortwave Infrared (3.9 µm) imagery (above) showed the thermal anomaly or “hot spot” (black to yellow to red enhancement) associated with lava flows from active fissures in the East Rift Zone on 06 June.

GOES-15 Visible (0.63 µm) images (below) showed clouds of steam from the East Rift Zone drifting to the south-southwest; a hazy plume of volcanic fog or “vog” was also evident, which was being transported farther to the southwest by the northeasterly trade wind flow.

GOES-15 Visible (0.63 µm) images, with hourly plots of surface reports [click to play MP4 animation]

GOES-15 Visible (0.63 µm) images, with hourly plots of surface reports [click to play MP4 animation]

A Suomi NPP VIIRS Visible (0.64 µm) image at 2307 UTC (below) showed clear skies over Kapoho on the eastern tip of the Big Island, with steam plumes from the active East Rift Zone fissures flowing southwestward.

Suomi NPP VIIRS Visible (0.64 µm) image [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) image [click to enlarge]

The corresponding VIIRS Shortwave Infrared (3.74 µm) image (below) helped to discriminate between the hot brightness temperatures of recent (and old) lava flows and the cooler brightness temperatures exhibited by regions of vegetation.

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) image [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) image [click to enlarge]

A closer look at the Kilauea East Rift Zone (below) provided a detailed view of the recent lava flow and active fissures, including the lava field that entered and covered Kapoho Bay a few days earlier. Note the appearance of numerous multi-colored pixels in the center of the lava field — the 3.74 µm I04 band detectors on the VIIRS instrument saturate around 385 K, so the hottest lava features which exceeded that brightness temperature threshold ended up being displayed as cold pixels (the so-called “wrap-around” effect). There is a Moderate-resolution M13 band (4.05 µm) on VIIRS which saturates at a much hotter 700 K; while it is a lower spatial resolution (750 meters, vs 375 meters for the I04 band), the M13 band can be useful for sampling the actual temperature of very hot features such as lava flows or wildfires.

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) image [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) image [click to enlarge]

Thanks to Jordan Gerth (CIMSS) and Eric Lau (NWS Pacific Region Headquarters) for providing the VIIRS imagery for this case.

Update: This link shows Landsat-8 and Sentinel-2 imagery before and after the Kapoho Bay lava flow.