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The 15 January 2022 climactic eruption of Hunga volcano, Tonga, produced an explosion in the atmosphere of a size that has not been documented in the modern geophysical record. The event generated a broad range of atmospheric waves observed globally by various ground-based and spaceborne instrumentation networks. Most prominent was the surface-guided Lamb wave (≲0.01 hertz), which we observed propagating for four (plus three antipodal) passages around Earth over 6 days. As measured by the Lamb wave amplitudes, the climactic Hunga explosion was comparable in size to that of the 1883 Krakatau eruption. The Hunga eruption produced remarkable globally detected infrasound (0.01 to 20 hertz), long-range (~10,000 kilometers) audible sound, and ionospheric perturbations. Seismometers worldwide recorded pure seismic and air-to-ground coupled waves. Air-to-sea coupling likely contributed to fast-arriving tsunamis. Here, we highlight exceptional observations of the atmospheric waves. [ABSTRACT FROM AUTHOR]

On 14 August 2021, the moment magnitude (Mw) 7.2 Nippes earthquake in Haiti occurred within the same fault zone as its devastating 2010 Mw 7.0 predecessor, but struck the country when field access was limited by insecurity and conventional seismometers from the national network were inoperative. A network of citizen seismometers installed in 2019 provided near-field data critical to rapidly understand the mechanism of the mainshock and monitor its aftershock sequence. Their real-time data defined two aftershock clusters that coincide with two areas of coseismic slip derived from inversions of conventional seismological and geodetic data. Machine learning applied to data from the citizen seismometer closest to the mainshock allows us to forecast aftershocks as accurately as with the network-derived catalog. This shows the utility of citizen science contributing to our understanding of a major earthquake. [ABSTRACT FROM AUTHOR]

The article presents a catalog of relocated earthquake hypocenters for Hawaii that provides unprecedented detail on the possible pathways for magma from the mantle to the volcanoes Kilauea and Mauna Loa. It mentions that the researchers used machine learning-based earthquake detection and relocation catalog of earthquakes from 2018 to 2022 to improve on earthquake location methods of hydrothermal fluid pathways connecting from the upper cluster to the crustal reservoir complex of Kilauea.

The article offers information on the California's earthquake warning system. It mentions that Thomas Heaton, lead scientist at the earthquake field office of the U.S. Geological Survey (USGS) in Pasadena, California drove to the office in darkness, imagining the fires, collapsed bridges, and crumbled buildings closer to the epicenter. It states that GPS sensors, though slower than seismometers, can capture earthquakes.

We recorded P and S waves traveling through the oceanic lithosphere-asthenosphere system (LAS) using broadband ocean-bottom seismometers in the northwest Pacific, and we quantitatively separated the intrinsic (anelastic) and extrinsic (scattering) attenuation effects on seismic wave propagation to directly infer the thermomechanical properties of the oceanic LAS.The strong intrinsic attenuation in the asthenosphere obtained at higher frequency (~3 hertz) is comparable to that constrained at lower frequency (~100 seconds) by surface waves and suggests frequency-independent anelasticity, whereas the intrinsic attenuation in the lithosphere is frequency dependent.This difference in frequency dependence indicates that the strong and broad peak dissipation recently observed in the laboratory exists only in the asthenosphere and provides new insight into what distinguishes the asthenosphere from the lithosphere. [ABSTRACT FROM AUTHOR]

After an earthquake, the earliest deformation signals are not expected to be carried by the fastest (P) elastic waves but by the speed-of-light changes of the gravitational field. However, these perturbations are weak and, so far, their detection has not been accurate enough to fully understand their origins and to use them for a highly valuable rapid estimate of the earthquake magnitude. We show that gravity perturbations are particularly well observed with broadband seismometers at distances between 1000 and 2000 kilometers from the source of the 2011, moment magnitude 9.1, Tohoku earthquake. We can accurately model them by a new formalism, taking into account both the gravity changes and the gravity-induced motion. These prompt elastogravity signals open the window for minute time-scale magnitude determination for great earthquakes. [ABSTRACT FROM AUTHOR]

The article discusses the application of citizen science in real-time earthquake monitoring which helped to understand the 2021 Haiti earthquake. It mentions how it took the help of seismometers in the entire country which record the earthquake. The citizen science network integrated data from its stations closer to the epicenter and published the earthquake's size and location. The network included 15 plug-and-play low-cost sensors Raspberry Shakes.

The article presents the discussion on public-private partnerships providing a method for vastly expanding sensor networks. Topics include monitoring the ocean and the atmosphere and US Geological Survey (USGS) seismometers detecting earthquakes; and smartphone sensors containing pressure, magnetic field, and infrasound.

The article informs on that following the discovery of magma at modest depth beneath Krafla Caldera, Iceland, an international coalition of scientists and engineers has been assembled to establish a long-term natural laboratory or testbed to take full advantage of this important discovery the Krafla Magma Testbed. It mentions that volcanologists rely on surface measurements from seismometers, Global Positioning System sensors, and radar satellites to guess its movements.

The article focuses on several researched related to solar cells, paleontology and earthquakes. Topics discussed include how tantalum-doped tungsten oxide forms almost ohmic contacts with inexpensive conjugated polymer multilayers to create a hole-transporting material with a small interface barrier, gravity perturbations in seismometer records from the great Tohoku earthquake and how fossilized pterosaur eggs that reveals that hatchling pterosaurs were likely not as precocial.

The article reports that planetary scientists are preparing for the demise of the U.S. National Aeronautics and Space Administration's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander, which detected more than 1300 quakes on Mars. The dust accumulating on the probe's solar panels has reduced power flows. It mentions that researchers are planning a seismometer network for the Moon similar to the lines of the InSight lander.

The mobility of the lithosphere over a weaker asthenosphere constitutes the essential element of plate tectonics, and thus the understanding of the processes at the [ithosphere-asthenosphere boundary (LAB) is fundamental to understand how our planet works. It is especially so for oceanic plates because their relatively simple creation and evolution should enable easy elucidation of the LAB. Data from borehole broadband ocean bottom seismometers show that the LAB beneath the Pacific and Philippine Sea plates is sharp and age-dependent. The observed large shear wave velocity reduction at the LAB requires a partially molten asthenosphere consisting of horizontal melt-rich layers embedded in melt-rich mantle, which accounts for the large viscosity contrast at the LAB that facilitates horizontal plate motions. [ABSTRACT FROM AUTHOR]

The article informs that according to a study published in the journal "Seismological Research Letters," researchers have repurposed an array of seismometers, which typically measure Earth's shaking, to detect the aurora borealis high above using Earth's magnetic field.

The article discusses geophysical exploration of the Earth's mantle that links plate tectonics with the formation of some major geological formations in the U.S., such as the Yellowstone supervolcano in Wyoming and Idaho and the Colorado Plateau. An overview is presented of the EarthScope program investigating Earth's interior using a wave of seismometers stretched across the U.S. and its components, including the USArray, the Transportable Array (TA), the Plate Boundary Observatory (PBO), and the San Andreas Fault Observatory at Depth (SAFOD). Also discussed is what EarthScope is revealing about the role of deep features in shaping the geology at the surface.

Two-thirds of Earth's surface is formed at mid-ocean ridges, yet sea-floor spreading events are poorly understood because they occur far beneath the ocean surface. At 9°50'N on the East Pacific Rise, ocean-bottom seismometers recently recorded the microearthquake character of a mid-ocean ridge eruption, including precursory activity. A gradual ramp-up in activity rates since seismic monitoring began at this site in October 2003 suggests that eruptions may be forecast in the fast-spreading environment. The pattern culminates in an intense but brief (∼6-hour) inferred diking event on 22 January 2006, followed by rapid tapering to markedly decreased levels of seismicity. [ABSTRACT FROM AUTHOR]

Investigates the influence of Iceland hotspot on the adjacent mid-Atlantic spreading center. Causes of volcanic formation; Implication of seismograph inspections; Description of the polarization anisotropy.

The article offers information on Chandrayaan-2 is which is developed by the Indian Space Research Organisation, the mission is planned to be launched to the Moon by a Geosynchronous Satellite Launch Vehicle. It mentions that Chandrayaan-2 has a seismometer for recording moonquakes. Its seismic measurements would supplement those from the Apollo landings, because readings from high latitudes would be sensitive to signals passing through different parts of the moon.

The article presents information on plans for a new research program, the Subduction Zone Observatory (SZO), which will study earthquakes, volcanoes, tsunami, and methane deposits in subduction zones. It states a workshop sponsored by the National Science Foundation that will meet in September 2016 will discuss what instruments the SZO will use, where it will be located, and potential costs. It speculates on the use of geodetic instruments and seismometers at the SZO to track crustal movements.

The article discusses plans for the Mars lander InSight now that it has landing on the planet. Topics include radio transmissions regarding the descent of the lander, the involvement of the U.S. National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) in the mission, and the role of a seismometer and a heat probe in the mission.

The article looks at Imaging Magma Under St. Helens (iMUSH), a research project in which researchers are imaging and mapping the subterranean networks below the active volcano Mount St. Helens. Geoscientist Alan Levander of Rice University in Houston, Texas and colleagues mapped the networks using seismometers, explosive shots, and natural earthquakes. Their imaging reveals two magma chambers below the volcano which may be connected. Topics include the electrical conductivity of rock and the 1980 eruption of Mount St. Helens.

The article focuses on the April 25, 2015 earthquake in Nepal and research that suggests the threat of earthquakes in that region of the Himalayan mountains was underestimated. It states that the driver of the earthquake is the slow collision of the Indian subcontinent with mainland Asia which is responsible for the growth of the Himalayan mountains. It mentions seismometer recording analysis of the quake and comments on areas at risk for landslide dams and flooding caused by the earthquake.

The article discusses the U.S. and Chinese's cooperation in seismology research on the Mariana Trench through placing seismometers in the Challenger Deep area of the Mariana trench to study earthquakes. [ABSTRACT FROM PUBLISHER]

An essay is presented on a method of teaching earthquake science in an introductory college geoscience course with the use of real-time seismic data from the U.S. Geological Survey (USGS) Earthquake Hazards Program Web site. The author describes her experiences in developing a teaching module in which students learn to create seismic risk-related decision-making analysis based on the interpretation of this available data.

In this article the authors have analyzed seismic noise to obtain new information on the structure of Earth's crust. By correlating the data from a month of ambient noise due in part to wave-wave interactions in the ocean 2 detected by 62 long-period seismograph stations in southern California, they determined the seismic response that they would have obtained from Earth's crust if they had applied forces at each of their stations. In particular, they measured the times that it took for seismic surface waves to propagate between every pair of stations. They then used lomographic techniques to create a map of seismic wave velocity with an unprecedented horizontal resolution of 75 to 100 km.

This article focuses on ocean microseisms. The first seismometers capable of measuring ground vibrations with periods of several seconds were installed in the early 20th century. Since then, the devices have recorded a continuous seismic hum, called "ocean microseisms." This hum is not the result of tectonic forces, but rather the response of the solid Earth to ocean wave-wave interactions. Ocean microseisms provide a record of the state of the oceans since the early 20th century and are a passive seismic source for probing the geological structure of Earth's upper crust.

The article discusses the finite-frequency seismometers by graduate student Raffaella Montelli, academic adviser Guust Nolet and seismologist Anthony Dahlen of Princeton University in New Jersey. In response to the problems in capturing the image of mantle plumes, the group strategically combine the primary seismic waves of two frequencies to form an image of the global mantle from a high-quality set. Moreover, the team narrows their research to achieve further developments in their techniques which resulted to a shift from primary to a new global image from secondary waves. This new moving ridge reacts differently to variations in rock temperature and composition.

The article reports on the installation of a seismometer array by the Great North China Initiative of the Natural Sciences Foundation of China (NSFC) across the North China Plain. The said installation is part of the initiative's measure against the region's geology and seismic risk. Mian Liu, a geophysicist at the University of Missouri in Columbia stressed the importance of such technologies for quake prediction. Moreover, to help shed light on this tectonic anomaly, the Deep Earth Lightening project involving the Chinese Earthquake Administration, the Chinese Academy of Sciences and the NSFC is wiring north China with nearly 800 portable broadband seismometers that will image the crust and upper mantle to map faults and explore craton evolution and dynamics.

The article reports that the budding regional tsunami warning system in the Indian Ocean may get little useful information from one key partner--India. The Indian government insists it will not release seismic recordings in real time, because if it were to resume nuclear testing, the detailed seismic signatures would immediately be broadcast to the world. Officials have also told Science they will not share online tide-gauge data, out of concern that such information could aid an aggressor attempting an invasion by sea. Delays in pinpointing an earthquake's location or confirming wave propagation could delay a tsunami warning. India's status as data holdout contrasts with its commitment to creating the region's most ambitious warning center for tsunamis and cyclone-generated storm surges. India has refused to hook up its vaunted array of seismometers to the Global Seismographic Network, 128 stations that record temblors and listen for signatures of nuclear detonations to help verify compliance with the Comprehensive Test Ban Treaty, which India has not joined.

The article reports that every day, several of California's more than 1000 shifting faults shake some part of the state. This clearinghouse of earthquake data keeps check on the ones that rattle northern California. Sponsored by the University of California, Berkeley, and the U.S. Geological Survey, the site catalogs magnitude, depth, location, and other measurements for earthquakes dating back to 1967. One should check out near-real-time recordings from a network of seismographs scattered around northern and central California.