The Earth Story

How do Mosquitoes find their dinner? Mosquitoes are crepuscular feeders who hunt their blood hosts at dawn and dusk. But how exactly do they find them?

This is pretty magnificent - just about 2 years after flow stopped on the Lower East Rift Zone of Kilauea, walking across tephra and lava layers out to the Fissure 8 mound, pulling out an infrared thermometer, and checking the temperature of the gas vents still on the site. That's heat originally delivered during the eruption, still slowly leaking its way out. Make sure you watch the end where he gets a view from the summit of fissure 8, into its heart, down the other cones left by the various fissures, and out to the ocean.

What is a plate? Often on this page you’ll hear me talking about plate motion, plate tectonics, or plate collisions as processes that form mountains and reshape the Earth’s surface. But, what exactly is a plate, to a geologist?

The amazing landscape of Wadi Rum (The Valley of the Moon) in southern Jordan

Fissure 8, the Cinder Cone that produced the largest lava flows in the 2018 Kilauea eruption, is still steaming and barren today. Here’s a visit. 

Salton Sea Geothermal Field The steam plumes in this photo are being emitted by a power plant near California’s Salton Sea. The Salton Sea is a disaster area – an enclosed basin below sea level that catastrophically flooded in the early 20th century (http://tmblr.co/Zyv2Js1b-EC2h). That low land occurs here for a reason; the land is being literally pulled apart.

Fulgurite: fossilised lightning strikes Fulgurites form when lightning strikes the ground and almost instantaneously melts the silicate minerals it contacts. The melt then rapidly cools leaving a hollow tube with a glass rim behind, often with other sand grains stuck to the surface. These tubes mimic the shape of the lightning as it passed into the ground creating the spectacular geometric pattern seen in these fulgurites. - Watson Further Reading: http://bit.ly/1FCC2xb Image credit:

Ken smith http://www.geologues-prospecteurs.fr/dictionnaire-geologie/f/fulgurite/yoyoj3d1 

http://bit.ly/1AXiAOQ

Gyres and Eddies! I recently stumbled on a really amazing visualisation by NOAA, showing a view of what was described as "doughnuts" in the ocean (original link at the bottom of the post). These donuts are called Gyres and Eddies.

A unique view of a fire

We’ve discussed how fires can trigger cloud formation multiple times here at The Earth Story. Clouds form above fires and volcanic eruptions when massive amounts of heat cause a mixture of air and hot ash to be pushed upward to the level in the atmosphere where water begins condensing on the particles, creating a fully formed cloud in the sky where otherwise there would not have been one. Because of this unique method of formation, these clouds were named flammagenitus clouds in 2017.

This view of a flammagenitus cloud was taken out the window of an Oregon National Guard F-15c fighter jet flying near a wildfire in 2014. You can clearly see how the ash forms a column heading upwards through the atmosphere; the heat of the fire has warmed so much air that it is rising straight up through the atmosphere to the level where water begins condensing and the cloud changes to a white color.

-JBB Image credit: Oregon National Guard/Nasa EOhttp://earthobservatory.nasa.gov/NaturalHazards/view.php?id=84129 Reference: https://www.theweathernetwork.com/news/articles/cloud-atlas-leaps-into-21st-century-with-12-new-cloud-types/80685/

Watch out guys and gals.. we've got a badass over here! This is Pedro Oliva, a professional Kayaker, and yes, that is lava. Oliva and his team, which includes extreme sports photographer Alexandre Socci, captured these images while rowing along the waters surrounding the active volcano, Kilauea, in Hawaii; as you do.. The water was near boiling point and at one point Pedro's oar even caught fire. Was this stunt worth the risk? That's a matter of opinion, but one thing is for sure, the resulting images are pretty awesome. -Jean See more images here: http://whenonearth.net/kayak-along-active-volcano/

Why does the ocean get deeper?

This is a map of the seafloor elevation or bathymetry in the Indian Ocean. The red and yellow areas represent shallow parts of the ocean; the blue and violet areas are deeper. Some obvious features, like Indonesia and the Ninety-East ridge, stand out obviously. If you look at the overall seafloor there is also another clear pattern. The Indian Ocean is shallow near the mid-ocean ridge, and the ocean gets deeper farther away from the ridge.

This property of the ocean floor is almost entirely due to heat. At mid-ocean ridges, the hot mantle comes up nearly to the depth of the seafloor. That mantle can be about 1200°C. Once that mantle melts to make ocean crust and the ocean crust solidifies and begins cooling, everything starts to contract. Over a period of millions of years, heat diffuses out of the ocean crust and even the upper mantle, cooling off the upper hundred kilometers of the planet. As the rocks cool, they contract and their density goes up, gradually dragging the ocean floor downwards under its own weight.

Some of the deepest places on Earth, including areas like the Mariana Trench, are found where there is exceptionally old oceanic crust. The older the oceanic crust, the colder it is and the denser it is, and the more it wants to sink into the planet.

This feature is observed on land as well. Where the land surface was recently rifted or active, it can be warmer than an ancient, cold continent. As this land surface cools, it will settle and subside, creating space for sediment or water to flow in and be trapped.

This simple story still leaves room for some complexities – for example, right next to the Sunda trench in this photo, the ocean floor actually rises because it’s being bent just before it goes down the subduction zone. Other areas can be warmed up by volcanic activity or by extra heat coming up from the mantle.

-JBB

Image credit: https://go.nasa.gov/2o8a1NX

Read more: http://topex.ucsd.edu/geodynamics/07cooling.pdf http://www-gpsg.mit.edu/12.201_12.501/BOOK/chapter5.pdf

Ocean heat waves increasing

This is a map showing a huge pool of warm surface water that formed in the North Pacific Ocean from 2013-2015. This pool of warm water was so stagnant that many weather scientists and forecasters casually started referring to it as “The Blob”, and it took the monster 2016 El Niño event to force the extra warm water to disperse. This huge pool of warm water likely contributed to some of the extreme weather events that hit North America in that timespan, as there was nothing like it in the North Pacific Ocean in the available weather records. Although this event was unprecedented in this location, newly available science shows that this type of event is happening with increasing frequency around the world as a result of the warming triggered by human release of greenhouse gases.

A group of scientists from Switzerland working on this problem defined events like this one as a “Marine Heat Wave”; a situation where the ocean surface is warmer than it has been 99% of the time in the available record. Satellite records of ocean surface temperature in this work were taken back to 1982, a fairly short time for a climate analysis, but even with that they found an extremely strong signal. Just over the time span measured by satellites, the number of days where a given area records a marine heat wave has doubled. The Marine Heat Waves have also become more intense and last a lot longer, all with statistical significance.

These marine heat waves don’t just contribute to extreme weather on land – they do a lot of damage to the ocean as well. Warm waters allow blooms of algae that can affect ocean chemistry, push fish out of their normal zones, and trigger coral bleaching events. Combining the increase in these events observed in the satellite measurement era with model results for how increasing greenhouse gases will affect the atmosphere, if humanity reaches the limits of the Paris climate accord these marine heat waves will still increase in probability by a factor of 23. If humanity misses that goal…an increase of 3.5°C leads to 41x as many days with marine heat anomalies as there were before 1980, with an average length of 112 days.

Needless to say, an ocean where the surface is regularly spiking in temperature to that extent is a very different one from the ocean we see today.

-JBB

Image credit: http://bit.ly/2w7VMfZ

Original paper: https://www.nature.com/articles/s41586-018-0383-9

Dry Astronaut Alexander Gerst captured this photograph of Spain, Portugal, Morocco, and the Straits of Gibraltar from the International Space Station last Sunday. Much of Europe has been parched by the recent heat waves and as a consequence Spain and Portugal look as brown as the Sahara Desert to the right of the frame. You can see a couple dust plumes coming off of Portugal, in addition to a smoke cloud fed by fires burning in the Algarve region. -JBB Image credit: ESA/NASA/Alexander Gerst https://flic.kr/p/L8ue4n

Real time video of a pahoehoe lava lobe advancing on the plains of Kilauea, Hawaii

An urban heat hole Northern India is covered in low lying cloud and smog in this satellite image, as it so sadly often is, in this case with the exception of a circular gap sitting right above the capital city of New Delhi allowing a glimpse of the subcontinent to shine through. Better known as the urban heat island effect, these holes reveal the locations of major cities when the ambient conditions are right for the low fog to form and the additional heat generated by the miles of buildings and concrete to evaporate the mist above or prevent its formation by drying out the city air below the saturation point. Researching this effect is useful in many disciplines, from air pollution assessment to air traffic control where the new understanding will help improve weather prediction, in this case especially during the winter months when the fogs tend to cover the northern Indian plains. Using satellite images the team also found similar fog holes over China, Europe, and the USA. Loz Image credit: NASA https://go.nasa.gov/2ChHrmL

Mudpot known as “Mud Volcano” in Yellowstone