Zamama (volcano)

[1][2] This volcanic center erupted after the Voyager 1 flyby in 1979, making it one of the few planetary volcanoes known to have activated during this generation's lifetime.

Zamama has a fissure-fed-type flow that is 150 km (93 mi) long with temperatures of 1,100 K (830 °C; 1,520 °F),[1] and the volcanic center site has explosive and effusive eruption characteristics.

Remote sensing instruments built on the Galileo spacecraft—the Near-Infrared Mapping Spectrometer (NIMS), Solid-State Imager (SSI), Photopolarimeter-Radiometer (PPR)—collect and analyze volcanism on Io's surface.

Since there are no samples collected from Io, all of the interpretations are made by studying albedo effects, morphology and/or spectral variations in Galileo data.

[6] The NIMS instrument detected activity at Zamama lasting longer than one year; therefore, it is considered the persistent type.

A couple techniques aided in the making of Io's topography, such as "3D" stereo photogrammetry (SP) and "2D" photoclinometry (PC).

Multiple steep-sided shield volcanoes lie in this area: Zamama appears to have been inactive during the 1979 Voyager 1 visit, or, it may have been buried by the Volund deposits.

Images show them as bright rings, placed within the dark lava flows, with diameters of about 370 km (230 mi).

[8] Galileo's NIMS instrument collected data on volcanic emissions to analyze the power output.

These interpretations might be a sign that current shield volcanoes will follow this pattern and transform to caldera-forming eruptive sites.

Image of the Zamama volcanic center, taken by Galileo in July 1999
Lava flow field on Zamama. Image was captured using Solid-State Imaging during the Galileo mission.
Zamama region on Io showing three volcanoes (Zamama A, B, and C) marked by white arrows. Zamama (A) shield volcano and the dark main flow complex spreading eastward.
The graph of eruption rate shows plunges which indicate lessening in diffusive activity or cooling of old flow surface. As well, it shows a spike, which indicates the beginning of a new eruption. The power output flux graph compares Zamama with other Ionian volcanoes of the same eruptive style.
Zamama has lower volumetric emission rates, compared with other Ionian volcanoes of the same eruptive style, and is more powerful than its terrestrial counterparts such as the volcano Kīlauea in Hawaii.
Model demonstrating how caldera volcanoes collapse.