Mi(ni)Geo

The Grímsvötn crater lake formed during the May 2011 eruption. (via Dave McGarvie)

The Hawaiian Islands were formed as the Pacific Plate moved westward over a geologic hot spot. The most populous Hawaiian Island, Oahu, is dominated by two large shield volcanoes that range in age from two to four million years old. However, a fair number of smaller and much younger volcanic craters are also present on Oahu, such as Diamond Head Crater pictured above. These younger eruptions were also much smaller in lava output, and much more explosive in nature than the older shield lavas. The younger volcanic craters are all less than 500,000 years old. They formed after Oahu had moved well off the hot spot and the main shield volcanoes had gone dormant for at least two million years. For example, Oahu is now over 200 mi (320 km) from the still-active Kilauea, on the Big Island, consistent with the modern rate of plate motion of four inches (about 10 cm) a year. What caused these younger eruptions of the Honolulu Volcanic Series so long after the island had moved off the hot spot, their precise ages of eruption, and whether they will erupt again, are current points of research and debate among geoscientists. Photo taken on June 12, 2008. Credit: Charles W. Carrigan. (via EPOD)

This striking photograph from the International Space Station features two examples of circular landscape features—labeled as craters—that were produced by very different geological processes. (vía NASA Earth Observatory)

Gullies in Bloom (by Lunar and Planetary Institute)

This observation shows mid-latitude-type gullies and dark and light materials. There are dunes in this crater as well (east of the gully aprons). One of the more stunning features is the gully formation right outside the center swath of the full image. ASU-IPF-3254

Mount Kilimanjaro’s peak in north-eastern Tanzania captured by the US-operated GeoEye-1 satellite. Mount Kilimanjaro rises from the plains to an elevation of 5,895 metres, the highest in Africa and the world’s largest free-standing mountain - it is also an active volcano. Credit: GeoEye / SPL / Barcroft Media. (via Telegraph)

Between 1 and 2 PM (Hawaiian time) on August 3, the floor to the Pu`u O`o crater collapsed in spectacular fashion. (…) You can clearly see the hardened floor of the crater begin to slump in the middle and over the course of 30-40 minutes, collapse into the Pu`u O`o crater. At the same time this was happening, a breach formed in the Pu`u O`o cone and a lava flow began on the flanks of Kilauea - this is typical for a spatter cone like Pu`u O`o as they are made of loosely consolidated material spit out during the basaltic eruptions of the vent. So, sometime lava will punch through a weak spot in the base of a cone and produce a lava flow, much like what we see now. (via Eruptions)

Stratigraphy of Kasimov Crater Fill (by Lunar and Planetary Institute)

This image shows layered sedimentary rocks and ripples that fill and surround Kasimov crater. These layered deposits may have formed through the accumulation of sediment that was transported into this crater by blowing wind. The crater interior contains a sequence of layers that are remnants of the material that originally infilled the crater. These sediments form an extensive deposit that once covered the floor of the surrounding larger crater.

A DigitalGlobe satellite image shows the eruption and lava flow of Mount Merapi, Indonesia. The volcano on the outskirts of Yogyakarta city in Central Java began spewing searing hot gas and ash clouds [in October-November 2010]. Picture: REUTERS/DigitalGlobe (via Telegraph)

Springtime at Marsʼ South Pole (by Lunar and Planetary Institute)

About two-thirds of the image is covered by part of the southern polar ice cap and other scattered ice deposits, near a feature known as Ulyxis Rupes. Ulyxis Rupes is a large cliff with a length of 390 km and a height of up to 1 km. The left side of the image is dominated by the polar capʼs ice shield, which is covered by dark dusty material that hides the bright ices beneath. (…) Just northward of the ice shield, about halfway across the image, there are large ice deposits that are heavily covered by overlying material blown into long dunes by the prevailing winds in this region. The orientation of the dunes suggests the wind must come predominantly from the northwest. With increasing distance from the south pole, ice becomes confined to larger impact craters, such as the one in the top right of the image. (…) Puzzling parallel structures in the martian dust can be seen in the bottom right quarter of the image. Although their origin is uncertain, it is possible that they are the result of underlying ice deposits, permanently frozen because they are protected by overlying dust and rocks. Image taken in January 2011.

Many layers are present in the wall of Euler crater. The layers are interpreted to be individual lava flows that formed the lunar maria. LROC NAC M124763045LE, image width is 500 m. Credit: NASA/GSFC/Arizona State University. (via LROC)

Iso-Naakkima, Mesoproterozoic Impact Crater (by jvanne)

Gravimetric measurement with colours and contours, shaded height model made from the laser scanning material of National Land Survey of Finland.

A small amount of impact melt pooled and froze on the floor of this Copernican impact crater, and is 90 x 70 m in size. LROC NAC M111972680LE, image width is 750 m. Credit: NASA/GSFC/Arizona State University. (via LROC)

Puyehue Cordón Caulle Volcanic Complex emitted a pale plume of gas and ash on August 18, 2011. Activity started on June 4, 2011. The ongoing eruption has been characterized by explosive emissions of ash and larger tephra, as well as the outpouring of lava typical of an effusive eruption. Evidence of both styles of eruption are visible in this natural-color satellite image, acquired by the Advanced Land Imager (ALI) aboard Earth Observing-1. A billowing ash plume indicates the explosive nature of the eruption. A fresh lava flow, darker than most of the surrounding, snow-covered landscape, illustrates the effusive aspect of the eruption. Signs of an older eruption are visible to the southwest (lower left) of the fresh lava. A diagonal line of vents and craters marks the location of an eruption that started on May 24, 1960—only 38 hours after a magnitude 9.5 earthquake occured under the Pacific Ocean, about 200 kilometers (120 miles) away from Puyehue Cordón Caulle. This is one of the few eruptions conclusively linked to earthquake activity. Downslope from the vents are thick, snow-covered lava flows, similar in appearance to the lava emitted by the current eruption. (via NASA Earth Observatory)

A recent view of the trek Opportunity has made since landing on Jan. 25, 2004. The rover is now near Spirit Point. (NASA/JPL-Caltech/MSSS) (via Wired Science)

Thunder Sounds from the Vent in Halema’uma’u (by usgs)

Booming sounds from the vent in Halema’uma’u have been audible around the summit area of Kilauea for the past several days. Some of these sounds are caused by rocks striking the surface of the lava lake, but most are actually the sound of the vent walls cracking due to heating and expansion of rock. This video, from February 25, illustrates what this sounds like. Occasionally, these sharp reports and booms can be visually correlated to rocks exploding off the vent wall and showering fragments down onto the surface of the lava lake. Source: USGS Multimedia Gallery.