Studying Climate Variability By Reconstructing 2500 Years Of Volcanic Activity

Scientists from the Desert Research Institute (DRI) and other institutions reconstructed 2500 years of volcanic activity to prove that volcanic eruptions contribute to climate variability. Gathering data from eruptions dating as far back as the Roman Era, the scientist published a study associating these with extreme shifts in the climate.

The study notes that eruptions in the tropic and high latitudes were primary contributors of climate variability. These were caused by large amounts of volcanic sulfate particles injected into the upper atmosphere which blocked incoming solar radiation from reaching the Earth's surface. The scientists also studied tree rings from long living bristlecone-pines and saw indications for extreme cooling after a large volcanic eruption. The same results were also derived from looking at ice cores from Greenland (see image above).

The study also shows that between 500 BC and 1000 AD, 15 of the 16 coldest summers followed large volcanic eruptions; four of them happening just after the largest volcanic events found in record.

Super Earths and Planetary Formation Recreated Using Laser Compression and Crystals

Researchers at the Lawrence Livermore National Laboratory (LLNL), Bayreuth University (Germany), LLNL and University of California, Berkeley were able to recreate the pressure and melting temperature of materials of a super-Earth planet at the core-mantle boundary.

Using laser shock compression, the team were able to measure the melting temperature of silica at 500 GPa (5 million atmospheres). Inside these planets, extreme density, pressure and temperature strongly modify the properties of the constituent materials. A planet's internal structure and evolution can be determined by measuring how much heat solids can sustain before melting under pressure.

Super-Earths can be defined as planets that are at least five times more massive than the Earth. These planets are lighter than gas giants like Neptune. They can be made up of gas, rock or both. To date, there are around 70 discovered super-earth like planets with hundreds more waiting to be classified.

The breakthrough that made this experiment possible was the ability to synthesize millimeter-sized transparent polycrystals and single crystals of stishovite, a high-density form of silica (SiO2) usually found only in minute amounts near meteor-impact craters. Ultrafast optical pyrometry and velocimetry at the Omega Laser Facility at the University of Rochester's Laboratory for Laser Energetics allowed the team to measure the melting temperature of the material at a much higher pressure.

Shock compression is a technique for inducing high pressures in materials, and high pressures. Usually explosives and impact guns were used to achieve strong shock waves. The new process of using lasers makes it possible to generate pressures far more higher than using traditional methods.

Experiment Recreates Asteroid Collision With Earth That Killed Off the Dinosaurs

An experiment that recreated the impact of an asteroid with the Earth that led to the extinction of the dinosaurs was done by researchers from the University of Exeter, University of Edinburgh and Imperial College London.

The scientists used a fire propagation apparatus to recreate the thermal pulse generated by an asteroid collision. Halogen lamps were also utilized to simulate the delivering thermal radiation (see image).

The experiment revealed that the long standing theory that the collision created firestorms around the Earth proved false. The heat generated by the experiment showed that the actual asteroid impact would have generated a heat pulse that lasted less than a minute. That is not enough time to ignite live plants.

Dr Claire Belcher from the Earth System Science group in Geography at the University of Exeter said, "By combining computer simulations of the impact with methods from engineering we have been able to recreate the enormous heat of the impact in the laboratory. This has shown us that the heat was more likely to severely affect ecosystems a long distance away, such that forests in New Zealand would have had more chance of suffering major wildfires than forests in North America that were close to the impact. This flips our understanding of the effects of the impact on its head and means that palaeontologists may need to look for new clues from fossils found a long way from the impact to better understand the mass extinction event."

San Andreas Fault Predicted To Trigger Strong Los Angeles Earthquake

Scientists at Stanford University used underground ambient seismic waves to predict that Los Angeles will experience a strong and large ground movements if an earthquake occurs along the southern San Andreas Fault, near the Salton Sea.

The Stanford scientists used weak vibrations under the Earth's core to measure and follow the movement of seismic waves. These waves are produced by the ocean waves crashing into the Earth's core. Although billions of times weaker than seismic waves generated by earthquakes, these ambient waves still follow the path an earthquake wave would.

Based on their measurements, an earthquake generated seismic waves will be funneled toward Los Angeles if the southern San Andreas Fault section of California were to experience an earthquake.

The scientists further predict that the seismic waves will be futher amplified when it reaches Los Angeles because the city sits atop a large sedimentary basin.