IRIS Earthquake Science

01/30/2021

Have a safe weekend!

01/29/2021

An Asteroid “Double Disaster” Struck Germany in the Miocene - Eos

"By analyzing sediments jostled by ground shaking, researchers have shown that two impact craters near Stuttgart were created by independent asteroid impacts rather than a binary asteroid strike."

https://eos.org/articles/an-asteroid-double-disaster-struck-germany-in-the-miocene

By analyzing sediments jostled by ground shaking, researchers have shown that two impact craters near Stuttgart were created by independent asteroid impacts rather than a binary asteroid strike.

01/29/2021

What might Earth’s next supercontinent look like? New study provides clues

"To study how Gondwana became Pangaea, the researchers mapped the continental plates over time, based on fossils and other deep-time records. And they explored how the position of these continents related to models of mantle flow—and the expected location of ancient upwellings and downwellings."

https://www.sciencemag.org/news/2021/01/what-might-earth-s-next-supercontinent-look-new-study-provides-clues

Researchers say giant landmasses form at regular intervals in predictable locations

01/29/2021

Drought, Not War, Felled Some Ancient Asian Civilizations - Eos

“Every handful of sand is radioactive,” said Tammy Rittenour, a professor of paleoclimatology and Quaternary geology at Utah State University whose lab specializes in the OSL technique but who was not involved in this study. When the sand is exposed to the Sun, its luminescence signal is known and effectively “zeroed.” And when the sand is buried—because, say, the canal that was carrying the sand was no longer flowing—it is exposed to the latent radioactivity of the surrounding sediments.

“There’s basically a proportionality between radiation exposure and luminescence,” and with knowledge of the rate of radiation exposure, it is possible to calculate when the sand was buried, said Rittenour."

https://eos.org/articles/drought-not-war-felled-some-ancient-asian-civilizations

Radiocarbon dating, luminescent sand grains, and climate records point to drought as the reason for the civilizations’ demise.

01/28/2021

Tectonics & Earthquakes of the Himalaya- Incorporated Research Institutions for Seismology

Regional compression produces broadly distributed earthquakes north of the Himalayan plate boundary. However, the historical earthquake record indicates that the largest occur on the shallow portion of the megathrust boundary. This animation discusses regional processes and focusses on the 2015 Nepal earthquake.

https://www.iris.edu/hq/inclass/animation/tectonics__earthquakes_of_the_himalaya

Regional compression produces broadly distributed earthquakes north of the Himalayan plate boundary. However, the historical earthquake record indicates that the largest occur on the shallow portion of the megathrust boundary. This animation discusses regional processes and focusses on the 2015 Ne...

01/28/2021

Supercomputers Simulate 800,000 Years of California Earthquakes to Pinpoint Risks

"Massive earthquakes are rare events—and the scarcity of information about them can blind us to their risks, especially when it comes to determining the danger to a specific location or structure.

Scientists are now working to improve the calculations of danger by combining maps and histories of known faults with the use of supercomputers to simulate potential shaking deep into the future in California."

https://blogs.ei.columbia.edu/2021/01/25/supercomputers-simulate-800000-years-california-earthquakes-pinpoint-risks/#.YA757hKTlO8.twitter

Scientists are working to improve their calculations of earthquake danger by combining maps of known faults with the use of supercomputers to simulate potential shaking deep into the future in California.

01/28/2021

GPS is not only useful for navigation and telling us where we are but GPS signals that bounce off the ground first can tell us about Earth's surface. Watch this animation to see how vegetation and snow affect GPS data. From @UNAVCO https://youtu.be/jCC3p_Qi-0I

01/27/2021

Lessons from COVID-19 Lockdowns with Raspberry Shakes

ADVENTURES IN TEACHING AND RESEARCH DURING COVID-19 LOCKDOWNS

https://raspberryshake.org/lessons-from-covid-19-lockdown-with-raspberry-shakes/

LESSONS FROM COVID-19 LOCKDOWNS WITH RASPBERRY SHAKES January 18, 2021 - Written by Alan Kafka, Weston Observatory, Boston College Alan Kafka’s research and teaching interests span the intersection of geophysics, earthquake science, environmental systems, and citizen science for the public

01/27/2021

Ghost forests are part of the evidence that a Great earthquake and devastating tsunami occurred last on January 26th, 1700 in the Pacific Northwest. How do we know this?

https://youtu.be/4xPbt8iiDRo

01/26/2021

Ghost Forests of the Pacific Northwest (evidence for Giant earthquake & tsunami)- Incorporated Research Institutions for Seismology

321 years ago a Great earthquake and devastating tsunami occurred in the Pacific Northwest. How do we know this?

https://www.iris.edu/hq/inclass/animation/ghost_forests_of_the_pacific_northwest_evidence_for_giant_earthquake__tsunami

Ghost forests are part of the evidence that a Great earthquake and devastating tsunami occurred last on January 26th, 1700 in the Pacific Northwest. How do we know this?

01/26/2021

Strong quake rattles San Juan - Temblor.net

"The relationships between the main recorded events and crustal structures have proved to be difficult to unravel in this region. Two historic events have produced surface ruptures in the area. The 1944 magnitude-7.0 earthquake and the 1977 magnitude-7.4 earthquake, both occurring in areas of compression generated sub metric fault scarps..."

https://temblor.net/earthquake-insights/strong-quake-rattles-san-juan-12377/

A magnitude-6.4 earthquake struck near San Juan, Argentina, this week, just days after the city commemorated a destructive earthquake three quarters of a century earlier.

01/25/2021

High-latitude seismometers typically tasked with peering inside the earth can also record electromagnetic undulations in the sky.

https://www.iris.edu/hq/science_highlights/earthscope_watches_the_sky

01/25/2021

2-minute takes on misunderstandings in Earth Science (GROUP)- Incorporated Research Institutions for Seismology

The epicenter is the map location on Earth’s surface, above where earthquake began. An earthquake actually begins inside the earth at the hypocenter. Learn more!

https://www.iris.edu/hq/inclass/animation/2minute_takes_on_misunderstandings_in_earth_science_group

Earth science is not simple. It frequently deals with difficult concepts, abstractions, mathematical laws, and theory. With this series of animations under 2 minutes, we hope to address common misunderstandings, misconceptions and myths.

01/25/2021

OPEN ACCESS SCIENTIFIC PAPER - Diffuse Tectonic Deformation in the Drum Mountains Fault Zone, Utah, USA: Testing the Utility of Legacy Aerial Photograph-Derived Topography

"The Basin and Range province in the western United States hosts numerous low-slip-rate normal faults with diffuse and subtle surface expressions. Legacy aerial photographs, widely available across the region, can be used to generate high-resolution digital elevation models of these previously uncharacterized fault systems. Here, we test the limits and utility of aerial photograph-derived elevation products on the Drum Mountains fault zone—a virtually unstudied and enigmatic fault system in the eastern Basin and Range province of central Utah. We evaluate a new 2-m digital surface model produced from aerial photographs against other remotely sensed and field survey data and assess the various factors that contribute to noise, artifacts, and distortions."

https://www.frontiersin.org/articles/10.3389/feart.2020.600729/full

01/24/2021

Fossilized lightning bolts reveal when ancient storms struck

"When a lightning bolt strikes a mountaintop, it can melt rocks in a flash, leaving a narrow glassy scar called a fulgurite. Now, researchers have shown that these fossilized thunderbolts are geological clocks that record the passage of time. The technique offers geologists a way to date thunderstorms from tens of thousands of years ago, and could give them a window into ancient climate patterns."

https://www.sciencemag.org/news/2020/12/fossilized-lightning-bolts-reveal-when-ancient-storms-struck

New geological dating system could show when glaciers retreated

01/24/2021

Today’s Earth system challenges are far more complex and urgent than those that existed in 1879 when the USGS was established.

Here is their new Science Strategy for 2020-2030.

http://ow.ly/s4wE50DeqRL

01/23/2021

Have a safe weekend! (Comic: Calvin and Hobbs)

01/22/2021

Overturning in the Pacific May Have Enabled a “Standstill” in Beringia - Eos

"Planet Earth pulled out all the stops, it seems, to enable the first humans to reach North America. When a glacial period lowered sea levels and turned parts of the Bering Strait into a land bridge, a warm ocean current shielded that region from the worst cold, turning it into a refuge where ancestors of the first Americans found shelter for thousands of years.

Evidence of that current, which doesn’t exist today, was published recently in Science Advances."

https://eos.org/articles/overturning-in-the-pacific-may-have-enabled-a-standstill-in-beringia

During the last glacial period, a vanished ocean current may have made the land bridge between Asia and the Americas into a place where humans could wait out the ice.

01/22/2021

Earth Science Week | Rock Talk Series - Igneous (Video 2/4)

Learn about igneous, sedimentary and metamorphic rocks in this video from the Utah Geological Survey!

https://youtu.be/voGBodQnqQU

Volcanoes, magma, and lava create some of the youngest rocks on Earth in many different forms and sizes.Follow us:Facebook: @UTGeologicalSurveyInstagram: @ut...

01/22/2021

Recent Earthquake Teachable Moment for the Philippines M7.0 earthquake

https://www.iris.edu/hq/retm/event/6787

01/21/2021

Tiny ground motions from M7.0 earthquakes in the Philippines measured in North America

Watch the waves from the M7.0 earthquake SE of Pondaguitan, Philippines roll across seismic stations in North America.

This animation, called a Ground Motion Visualization (GMV), shows the motion of the ground as detected on seismometers across North America - each dot is a seismic station and when the ground moves up it turns red and when it moves down it turns blue.

Waves generated by an earthquake travel around and through the earth, but they get smaller (attenuate) as they move away from the earthquake location, just like ripples in a pond. Once the earthquake waves are far enough away from the location where the earthquake occurred they can no longer be felt by people, BUT they can still be detected by sensitive seismic instruments. That's what this animation is showing - the waves from the M7.0 earthquake traveling both through the earth and across earth's surface - in the continental US the earthquake the waves are much too small to feel but not too small to measure. The scale is along the bottom. It is in micrometers (microns). For reference, the diameter of a human hair is ~50-75 microns.

The green triangle is the station recording the seismogram shown along the bottom. The red line is the "great circle path" between the reference seismometer (green triangle) and the earthquake location.

*Some of the instruments look like they are experiencing shaking before the seismic waves arrive. This is due to the setting of the animation and the calibration of the seismic instrument.

**The video is not reflecting the actual speed of the waves; it has been sped up. The time is shown along the bottom.

***If you look carefully you will see that there are Canadian stations used in this animation, primarily along the western coast and adjacent to Alaska. Not every seismic instrument in the US, Canada or Mexico can be used in this type of animation.

This particular GMV is generated using the vertical component of our Ground Motion Visualization (GMV). To produce a better coverage, the video is based on all available stations from any FDSN data center, using the fedcatalog service (http://service.iris.edu/irisws/fedcatalog/1/). The video uses the available BHZ, LHZ, or HHZ channel to produce the video, therefore provides a better coverage.

To see more GMV's visits http://ds.iris.edu/spud/gmv/17971022
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01/21/2021

Highly explosive basaltic eruptions driven by CO2 exsolution

OPEN ACCESS SCIENTIFIC PAPER - Highly explosive basaltic eruptions driven by CO2 exsolution

"The most explosive basaltic scoria cone eruption yet documented (>20 km high plumes) occurred at Sunset Crater (Arizona) ca. 1085 AD by undetermined eruptive mechanisms. We present melt inclusion analysis, including bubble contents by Raman spectroscopy, yielding high total CO2 (approaching 6000 ppm) and S (~2000 ppm) with moderate H2O (~1.25 wt%). Two groups of melt inclusions are evident, classified by bubble vol%. Modeling of post-entrapment modification indicates that the group with larger bubbles formed as a result of heterogeneous entrapment of melt and exsolved CO2 and provides evidence for an exsolved CO2 phase at magma storage depths of ~15 km. We argue that this exsolved CO2 phase played a critical role in driving this explosive eruption, possibly analogous to H2O exsolution driving silicic caldera-forming eruptions. Because of their distinct gas compositions relative to silicic magmas (high S and CO2), even modest volume explosive basaltic eruptions could impact the atmosphere."

https://www.nature.com/articles/s41467-020-20354-2

Mechanisms that drive highly explosive eruptions of low-viscosity magmas, such as at Sunset Crater volcano, remain uncertain. Here, the authors present evidence for an exsolved CO2 phase ~15 km beneath Sunset Crater that was the critical driver of rapid magma ascent leading to the explosive eruption...

01/21/2021

IRIS is a consortium of over 100 US universities dedicated to the operation of science facilities for the acquisition, management, and distribution of seismological data. IRIS programs contribute to scholarly research, education, earthquake hazard mitigation, and verification of the Comprehensive Nuclear-Test-Ban Treaty.

https://www.iris.edu/hq/about_iris#vision

01/20/2021

"CSU geology experts study the active land California inhabits to better understand earthquakes and predict the location and intensity of future temblors."

https://www2.calstate.edu/csu-system/news/Pages/the-faults-in-our-earth.aspx

01/20/2021

OPEN ACCESS SCIENTIFIC PAPER - Apparent earthquake rupture predictability

"To what extent can the future evolution of an ongoing earthquake rupture be predicted? This question of fundamental scientific and practical importance has recently been addressed by studies of teleseismic source time functions (STFs) but reaching contrasting conclusions. One study concludes that the initial portion of STFs is the same regardless of magnitude. Another study concludes that the rate at which earthquakes grow increases systematically and strongly with final event magnitudes. Here we show that the latter reported trend is caused by a selection bias towards events with unusually long durations, and by estimates of STF growth made when the STF is already decaying. If these invalid estimates are left out, the trend is no longer present, except during the first few seconds of the smallest events in the dataset, Mw5–6.5, for which the reliability of the STF amplitudes is questionable. Simple synthetic tests show that the observations are consistent with statistically indistinguishable growth of smaller and larger earthquakes. A much weaker trend is apparent among events of comparable duration, but we argue that its significance is not resolvable by the current data. Finally, we propose a nomenclature to facilitate further discussions of earthquake rupture predictability and determinism."

https://academic.oup.com/gji/advance-article/doi/10.1093/gji/ggaa610/6054996

Overview talk - https://www.youtube.com/watch?v=xcdUvyhdY6E&feature=youtu.be

01/19/2021

"Yellowstone hosts thousands of thermal features which have diverse chemistries and origins. The most iconic features, like Old Faithful, are alkaline, and have a slightly neutral pH. Some Yellowstone features, however, can be acidic enough to break down the very rock that hosts them!"

https://www.usgs.gov/center-news/where-do-acid-sulfate-hot-springs-come-and-why-are-they-important?utm_source=twitter&utm_medium=social&utm_term=80cabe06-625c-4f96-bc59-31ae791e09c4&utm_content=&utm_campaign=usgsvolcanoes&qt-news_science_products=4#qt-news_science_products

01/19/2021

TEACHERS TOOLBOX - This activity allows the students to select a global region of interest and to interrogate the earthquake catalog to obtain quantitative data on the rate of occurrence of earthquakes of various magnitudes within their chosen region.

https://www.iris.edu/hq/inclass/lesson/exploring_rates_of_earthquake_occurrence