Sentinel-1 intensity images displayed in SAR geometry

Sentinel-1 intensity images are now also displayed in the SAR imaging geometry: the image's y-axis is denoted as "azimuth" and corresponds to the radar flight direction, whereas the image's x-axis is the "slant range" and corresponds to the radar line-of-sight direction. The antenna is right-looking, meaning that the radar is looking from the left-side of the image. The pixel spacing is 2.3 x 14.1 m in range and azimuth respectively (SLC IW products, ESA).

These intensity images in SAR geometry are made available only for the "zoomed" 2x2km crop around the crater. Because the during the geocoding process (i.e., Range Doppler Terrain Correction) the SAR images suffer distorsions, visualizing the images in the original SAR geometry can prove useful to detect small changes in the scene.

The "timeseries", "imgplayer" and "imgslider" webpages have been updated to visualize these images.


New monitored volcano: Lewotolo volcano (Indonesia), following the communication from GVP on its ongoing unrest.


Monitoring priorities

Monitoring priorities have been introduced, whereby each volcano is assigned a "priority level" defining the amount of downloaded/processed data:

- high: all available S1 + S2 + S5P products

- medium: all available S2 + S5P products & selected S1 products (e.g., specific orbit, rate, etc.)

- low: selected S1 + S2 + S5P products (e.g., specific orbit, rate, etc.)

- pause: download/process of S1 + S2 + S5P products are paused, and reactivated in case of increased eruptive activity

The prioriy level assigned to each volcano can be visualized from the volcano webpage (in the gray information section on the top-left). Hovering on the level allows the user to visualize details on which data is downloaded/processed.

The priority levels will be subject to modifications in case of variations of the volcano's eruptive activity. Such modifications can result from internal data evaluation (MOUNTS), or communication with external sources (e.g., volcano observatories, MIROVA, HOTVOLC, GVP, VAAC, etc.).


New monitored volcanoes (reaching >50 monitored volcanoes worldwide)


- Guatemala: Santa María

- Costa Rica: Poás, Turrialba, Rincón de la Vieja

- El Salvador: San Miguel

- Colombia: Nevado del Huila

- Colombia-Ecuador: Chiles-Cerro Negro

- Ecuador: Reventador

- Chile: Láscar, Planchón-Peteroa, Nevados de Chillán

- Argentina-Chile: Copahue


- India: Barren Island

- Indonesia: Sinabung, Kerinci, Merapi, Semeru, Ijen, Raung, Dukono

- Japan: Asosan

- Russia: Sheveluch


- Papua New Guinea: Manam, Bagana, Langila

- Vanuatu: Aoba, Yasur

(Products are being downloaded from now onwards; older data is progressively being downloaded/processed.)


Color-coded scales and associated automatic email alerts

Color-codes are now assigned to the detected 'SO2 mass', 'thermal anomalies', and 'deformation', and are reflected in the home-page table. Automatic email alerts are sent to specified users, which are customized based on the desired alert-type, alert-level, and volcano of interest. Contact to get more information and/or register.


Improved SO2 detection

(1) The filters used to detect SO2 contaminated pixels (concentration >1 DU + morphological filter, Valade et al. 2019) have been replaced by the L2-product flag "sulfurdioxide_detection_flag" developed by DLR-IMF (ref). This flag identifies pixels with a concentration >0.35 DU, and takes into account whether neighboring pixels also fulfill this criterion in order to minimize false-positive detections. This now allows MOUNTS to detect smaller SO2 plumes.

(2) The SO2 mass detected in a 500x500 km box centered on the volcano is now attributed to the volcano only if SO2 is also detected in a 100x100 box around the volcano. This now allows MOUNTS to minimize false-detections due to SO2 emissions by neighboring volcanoes.

These upgrades are now operational, and re-processing of the archive dataset is ongoing.


New monitored volcano: Telica (Nicaragua).


New monitored volcano: Ubinas (Peru).


Sentinel-2 images are now also displayed as true color images (visible bands B4-B3-B2, 10m resolution), with hot pixels enhanced using SWIR infrared bands B12-B11-B8A (20m resolution).


New feature in timeseries webpage: the various image types are now easily changeable using radio-buttons displayed on the left side of the image (e.g., Sentinel-2 image types: 'visible + infrared', 'infrared', 'infrared + detection'). These can also be changed in the "page options" menu.


New timeseries webpage: the page has been restructured to display parameters derived from the analysis of Sentinel-1 (deformation, coherence, intensity), Sentinel-2 (hotspots) and Sentinel-5P (SO2) products in distinct subplots, together with images associated to each timeseries. The old page version is still accessible from the "page options" menu, following the link "collapsed timeseries".


New products available: images are now also plotted on a "zoomed" crop around the volcano summit (2x2 km for Sentinel-1 & 2 images, 100x100 km for Sentinel-5P images).


New monitored volcanoes: Nevado del Ruiz (Colombia), Villarrica (Chile), Masaya & Momotombo (Nicaragua), Ibu (Indonesia), Sakurajima (Japan).


Sentinel-1 SAR intensity images are now also displayed after speckle-filtering (CNN-based speckle filter: Davis et al. 2020, IGARSS).


New monitored volcano: Michoacan-Guanajuato volcanic field (Mexico), in response to the seismic crisis initiated early January 2020. Real-time monitoring ended on 2020-03-06 following a significant decrease in seismic activity.


New monitored volcano: Taal (Philippines), in response to the eruptive crisis started early January 2020.