The Earth Story

The latest #AntarcticLog by Karen Romano Young features some of the lesser-known #climatechange indicators, i.e., the “canaries in the coal mine." https://tinyurl.com/y7tvhtdm

What’s it like to have to lasso icebergs to keep your ship from sinking? Or what are some of the strange rituals scientists go through when crossing the equator for the first time? In our newest Third Pod from the Sun episode, ESRI Chief Scientist Dawn Wright talked about her experiences drilling in the deep sea. Listen now. 

Sea ice, which is frozen seawater, can take many different forms depending on its surrounding conditions. If there are waves on the ocean surface, sea ice forms as ‘pancake’ floes ‐ small circular pieces of ice.

In a new study in Journal of Geophysical Research – Oceans, researchers present an analysis of images captured by buoys that drift with the ice in the Arctic during freeze‐up. The images show how pancake floes evolve over time as a result of wave and freezing conditions.

Pancake ice floes form when there are ocean surface waves that prevent the formation of smooth sheet ice. The pancake floes can grow laterally as more frazil crystals in the ocean adhere to their sides, and they can also weld together into sheets of cemented pancakes. ​

The researchers compared their observations to what different theoretical models would predict for the observed conditions. These comparisons can be used to inform the development of new large‐scale models for sea ice evolution, which is important for polar climate.

Blood Falls spills it’s subglacial iron-rich brine into the western end of Lake Bonney, emerging from the end of the Taylor Glacier, Taylor Valley Antarctica. The McMurdo Dry Valleys Long-Term Ecological Research project has been studying the valley ecosystems since 1993.

Scientists simulate dense and dilute pyroclastic currents flowing down Indonesia’s Merapi volcano during its 5 November 2010 eruption. The concentrated block-and-ash flow is in red, the dilute ash-cloud surge is in blue. Yellow to green colors and contour lines are the thickness of surge deposits. Time is sped up: one second in the video represents 50 seconds in reality.

This new model, which simulates the behavior of surging ash clouds, may help scientists to better predict the hazards associated with the deadliest type of volcanic flows.

Read more at eos.org. 

Credit: Kelfoun et al.

Small mountain glaciers play a big role in recharging vital aquifers and in keeping rivers flowing during the winter, according to a new study published in Geophysical Research Letters, a journal of the American Geophysical Union.

The study also suggests that the accelerated melting of mountain glaciers in recent decades may explain a phenomenon that has long puzzled scientists – why arctic and subarctic rivers have increased their water flow during the winter even without a correlative increase in rain or snowfall.

These photos show University of Alaska Fairbanks researcher Anna Liljedahl coring the glacier snow pack on Jarvis Glacier to measure snow density in order to estimate how much water is stored in the later winter snow pack before the snow melts, and putting up a wind shield around a gauge that she installed on Jarvis Glacier to measure rainfall. They also show UAF researchers hiking between the glacier mass balance stakes on Jarvis Glacier to measure how much snow and ice melted over the summer, and taking a water sample for geochemical analysis at the mouth of the Jarvis Glacier. 

The bottom images show a before and after photo of Gulkana Glacier. The top photo shows the Gulkana Glacier in 1967 when the US Geological Survey started their glacier mass balance monitoring program. The bottom photo is 49 years later in 2016 and shows the shrinkage of the glacier extent. The total loss of water from the glacier retreat equals a 25m deep water column spread out across the entire recent glacier area.

Read more at http://blogs.agu.org/blog/2017/07/21/mountain-glaciers-recharge-vital-aquifers/

Photo credits: USGS (Gulkana Glacier), Todd Paris/University of Alaska.

Using high-speed, high-definition cameras, researchers have tracked the motion of volcanic projectiles. The projectiles, which can be as small as an apple or as large as a van, can be launched as far as several kilometers from the volcano, causing destruction where they land.

The researchers analyzed the trajectory, rotation, collision, and deformation of the projectiles in-flight in a new study in Reviews of Geophysics. The results will allow scientists to make better predictions of the projectiles’ trajectory and landing impact.

This video show projectiles from the Batu Tara volcano in Indonesia. It shows ascending and descending parts of a block trajectory. On impact with the ground, the block forms an impact crater, then it bounces out of the crater and forms two more impact craters before bouncing on a hard, probably lava, surface and disappearing from the field of view. Other projectiles that fragment on impact with the hard surface can also be seen.

Credit: American Geophysical Union

Dear science enthusiasts, 

I’m burning up here at the Syracuse Lava Project, a collaboration between artist Bob Wysocki and geologist Jeff Karson at Syracuse University. These fearless (and a little crazy) men work together to melt, mix and pour homemade lava for both artistic and scientific projects. Bob and Jeff were nice enough to host me and an AGU colleague for three days of pouring and filming lava. The lava - at over 1,000 degrees C - generated so much heat that we had to stop filming twice because the camera overheated. No one got burned (luckily!) and we got to see something few people (let alone scientists) ever get to see - real-life lava flows. 

In this image, you can see Bob clad in his leather protection gear, operating the furnace. For this pour, we made the lava extra hot and poured it over wet sand. You can see that as the lava flows over the sand, it has vaporized the water in the sand and that water vapor causes the lava to bubble up. Next, we’ll be getting the lava even hotter and attempting to create a lava lake. 

Wish you were here, 

Lauren Lipuma

AGU public information specialist 

Greetings from the R/V Tangaroa, offshore the South Island of New Zealand.   At the moment we are deploying a Controlled-Source Electromagnetic instrument offshore the Canterbury Plains, which will allow us to measure sub-seafloor resistivity. Once the data are integrated with new multi-channel seismic reflection data that we plan to acquire next week, we will be able to characterize the distribution and geometry of one of the shallowest offshore freshwater aquifers in the world.   We are 12 days out on a 24 day research cruise. In the following weeks we plan to ground-truth our geophysical data by acquiring seafloor pore-water and water column samples where the groundwater is seeping into the sea to determine its origin and age.

You can follow our cruise on: www.facebook.com/marinegeologyseafloorsurveying/   The cruise is supported by a European Research Council grant (MARCAN) and NIWA.

In a new study, scientists modeled tsunamis that may have occurred on Mars billions of years ago. They conclude deposits on Mars’s northern plains may have come from asteroids slamming into a northern ocean billions of years ago, generating waves 300 meters (nearly 1,000 feet) high. The new study and the tsunami hypothesis lend support to the much-debated idea that Mars harbored a northern ocean billions of years ago.

This simulation shows the propagation of the tsunami waves as a function of time.

Read more at on AGU’s GeoSpace blog.

This animation is awesome and it’s the kind of stuff I wish scientists would share more. This is a computer generated animation of a tsunami generated by an asteroid hitting Mars’s northern basin, assuming there is an ocean present in that basin, and the waves from that tsunami washing up in the channels that run over Mars’s surface. It’s also really pretty!

Hey everyone,

Here is my first geoscience crossword. 

Cheers,

Xuan

(Twitter: @GeoXuan)

Oh dear no...I have too much work to do.

You know what? Answer in the comments and I might fill some in.

In the Mediterranean Sea, just east of Sicily, may lie the culprit responsible for many major earthquakes in the past 500 years and the associated 5-10 meter (16-32 feet) high tsunamis that followed, according to a study published in Tectonics, a journal of the American Geophysical Union.

Previously, the exact source of these seismic events was largely unknown. One potential source was the Malta Escarpment, found just 3-4 kilometers (1-2 miles) off the coast of Sicily – a step that scientists thought was a major active fault. New data from bathymetry and seismic profiling suggests that a strike-slip crossing the North Malta Escarpment (near Mt. Etna) could be the cause of these quakes.

Avoiding icebergs on Pluto. Special thanks to Emily Lakdawalla (@elakdawalla) for helping me find the image of the “icebergs” floating in Sputnik Planum. You can follow the complete series of AGU Cartoons at https://earth.stanford.edu/news/earth-and-space-science-cartoons

By analyzing an induced earthquake sequence, scientists found that human-caused earthquakes leave different seismic signatures than naturally occurring quakes, allowing seismologists to more successfully interrogate earthquake origins.