Magma chambers are pockets of molten rock that are close to the surface of the earth’s crust. These “hot spots” rise to the surface and create pressure. The hot spots can be caused by subduction (two plates colliding) or rift valleys (two plates pulling apart). Usually, thick plugs of solid rock many millions of tons keep the magma down, but pressure builds up and eventually the mountain erupts. The eruption usually spews magma out of a central vent until the pressure is relieved and the magma chamber is emptied, until it fills again.
Karymsky Lake is a crater lake located in the Karymsky volcano in Russia. With a radius of 5 km it was once one of the world’s largest fresh water lakes, but as a result of a recent eruption toxic gases turned this into one of the largest acid water lakes.
This is a rather amazing clip of liquefaction of sediments during the Mexico Earthquake on Tuesday. When shaken, water-saturated sediments lose all their strength and will start flowing. Mexico City is built on exactly these kind of sediments. Here you can actually see big slabs of concrete, part of a sidewalk, moving up and down as water flows beneath them in sediments that used to support the sidewalk’s weight.
The 1960 Valdivia earthquake (Spanish: Terremoto de Valdivia) or Great Chilean earthquake (Gran terremoto de Chile) of 22 May is the most powerful earthquake ever recorded. Various studies have placed it at 9.4–9.6 on the moment magnitude scale. It occurred in the afternoon (19:11 GMT, 15:11 local time), and lasted approximately 10 minutes. The resulting tsunami affected southern Chile, Hawaii, Japan, the Philippines, eastern New Zealand, southeast Australia and the Aleutian Islands.
Resembling some odd mineral alien we have a micromount (see https://bit.ly/1AjbRrW) of dark bubbly manganese oxide surrounded by yellow bubbles made of crystal sprays of the mineral Cacoxenite (see https://bit.ly/2vqgdaB). Nsutite is named after its type locality (from which it was first scientifically characterised and described) in Ghana, though it is a feature of manganese deposits worldwide. Typical material is massive rather than overtly crystalline, and dull grey or black in colour, while being quite hard (varying between 6.5 and 8.5 on Mohs scale). Its main use is as an electrode in zinc carbon batteries, though synthetic material is now used in most manufacture. The photo won image of distinction in the NIkon Small World photography competition.
Sorry for the delay, I’m about to head to field camp and had a major project I needed to get into email today.
Anyway, the US Geological Survey wrote a piece specifically on this issue today. Basically, the Hilina slump is a fault where, because of motion on Kilauea’s rift zones, part of the island is actually pushed out to the sea. There are faults in Hawaii, produced like this, that have produced major collapses, but historically this one has not. To trigger that kind of huge collapse and mega tsunami, the fault would have to have the right orientation with nothing else supporting it out to sea – probably why some of these collapses happen millions of years after the volcanoes stop being active.Â
There is no geologic evidence for past catastrophic collapses of Kilauea Volcano that would lead to a major Pacific tsunami, and such an event is extremely unlikely in the future based on monitoring of surface deformation. Kilauea tends to “slump”, which is a slower type of movement that is not associated with tsunamis, although localized tsunamis only affecting the island have been generated by strong earthquakes in the past.
The May 4 M6.9 earthquake resulted in seaward motion of approximately 0.5 m (1.5 ft) along portions of Kilauea’s south flank as measured by GPS stations across the volcano. A preliminary model suggests that the motion was caused by up to 2.5 meters (8 feet) of slip along the fault that underlies the volcano’s south flank, at the interface between the volcano and the ocean floor, about 7-9 km (4-6 mi) beneath the surface. This motion is within the expected range for a large earthquake on this fault. The earthquake was probably caused by pressure exerted by the magmatic intrusion on the south flank fault, following the pattern of past earthquake activity that has been observed during Kilauea East Rift Zone intrusions. A small, very localized tsunami did occur as a result of the fault slip. Similar local tsunamis were generated by past large earthquakes, including the 1975 M7.7 and 1868 ~M8 events, both of which resulted in multiple deaths along the south coast of the Island of Hawaii.
Adjustments on the south flank caused another ~9 cm (3.5 inches) of motion at the surface in the day after the earthquake, followed by another 2-3 cm (~1 inch) since May 5. This is higher than the normal rate of south flank motion (~8 cm (3 inches) per year) but is expected as the volcano adjusts after a combination of a magmatic intrusion along the East Rift Zone and a large south flank earthquake. We did observe minor ground ruptures on the south flank, but this is expected given the strength of the May 4 earthquake, and deformation data show that the south flank continues to move as an intact slump block.
Geologic history combined with models of south flank motion suggest that the likelihood of a catastrophic failure event is incredibly remote. There are certainly signs on the ocean floor for landslides from other volcanoes on the Island of Hawaii and from other islands, but none are associated with Kilauea. In addition, Kilauea has experienced much larger earthquakes and magmatic intrusions in the recent past. The large earthquakes of 1975 and 1868 were not associated with significant south flank landsliding, nor were major East Rift Zone intrusions in 1840 and 1924.Â
🔥 There is beauty in destruction🔥 