13 research outputs found
SCOPED: Seismic COmputational Platform for Empowering Discovery [Year 2]
This poster was presented at the NSF CSSI annual PI meeting in Houston, September 26-27, 2023. This summarizes the Year 2 efforts of the SCOPED project.The NSF funding awards are OAC-CSSI 2104052 [UAF/Tape], OAC-CSSI 2103621 [MINES/Bozdag], OAC-CSSI 2103701 [UW/Denolle], OAC-CSSI 2103741 [Columbia/Waldhauser], OAC-CSSI 2103494 [TACC/Wang]
Anelastic sensitivity kernels with parsimonious storage for adjoint tomography and full waveform inversion
We introduce a technique to compute exact anelastic sensitivity kernels in
the time domain using parsimonious disk storage. The method is based on a
reordering of the time loop of time-domain forward/adjoint wave propagation
solvers combined with the use of a memory buffer. It avoids instabilities that
occur when time-reversing dissipative wave propagation simulations. The total
number of required time steps is unchanged compared to usual acoustic or
elastic approaches. The cost is reduced by a factor of 4/3 compared to the case
in which anelasticity is partially accounted for by accommodating the effects
of physical dispersion. We validate our technique by performing a test in which
we compare the sensitivity kernel to the exact kernel obtained by
saving the entire forward calculation. This benchmark confirms that our
approach is also exact. We illustrate the importance of including full
attenuation in the calculation of sensitivity kernels by showing significant
differences with physical-dispersion-only kernels
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Initial results from the InSight mission on Mars
NASA’s InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018. It aims to determine the interior structure, composition and thermal state of Mars, as well as constrain present-day seismicity and impact cratering rates. Such information is key to understanding the differentiation and subsequent thermal evolution of Mars, and thus the forces that shape the planet’s surface geology and volatile
processes. Here we report an overview of the first ten months of geophysical observations by InSight. As of 30 September
2019, 174 seismic events have been recorded by the lander’s seismometer, including over 20 events of moment magnitude Mw
= 3–4. The detections thus far are consistent with tectonic origins, with no impact-induced seismicity yet observed, and indi-
cate a seismically active planet. An assessment of these detections suggests that the frequency of global seismic events below
approximately Mw = 3 is similar to that of terrestrial intraplate seismic activity, but there are fewer larger quakes; no quakes
exceeding Mw = 4 have been observed. The lander’s other instruments—two cameras, atmospheric pressure, temperature and
wind sensors, a magnetometer and a radiometer—have yielded much more than the intended supporting data for seismometer
noise characterization: magnetic field measurements indicate a local magnetic field that is ten-times stronger than orbital
estimates and meteorological measurements reveal a more dynamic atmosphere than expected, hosting baroclinic and gravity
waves and convective vortices. With the mission due to last for an entire Martian year or longer, these results will be built on by
further measurements by the InSight lander
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Seismic wavespeed images across the Iapetus and Tornquist suture zones
Closures of the Iapetus Ocean and the Tornquist Sea lead to the collision of the paleocontinents of Laurentia, Baltica and Eastern Avalonia during the Caledonian orogeny. It has been speculated that relicts of these two closures may be preserved within the crust or upper mantle. Over the past decades, numerous wide‐angle seismic profiles were gathered in northwestern Europe to search for related subsurface features. Although active source studies revealed detailed crustal structures across the Iapetus and Tornquist suture zones, there are relatively few clear three‐dimensional upper mantle images beneath this region. We use a new European crust and upper mantle model, EU30, determined based on continental scale, nonlinear adjoint tomography, to explore upper mantle structures across these two suture zones. Model EU30 reveals two fast anomalies within the upper mantle: one dips in a northwesterly direction down to approximately 400 km beneath the North Sea, and the other dips in a southwesterly direction down to nearly 250 km across the Tornquist Suture Zone. In addition, we observe a “gap” between the lithospheres of Laurentia and Eastern Avalonia across the Iapetus Suture Zone beneath the central British Isles. These seismic images suggest that heterogeneity related to the closures of the Iapetus Ocean and the Tornquist Sea have been preserved within the upper mantle over hundreds of millions of years
Lighting talk for SCOPED project, year 2
This one-slide lightning talk was presented at the NSF CSSI annual PI meeting in Houston, September 26-27, 2023. This summarizes the Year 2 efforts of the SCOPED project.The NSF funding awards are OAC-CSSI 2104052 [UAF/Tape], OAC-CSSI 2103621 [MINES/Bozdag], OAC-CSSI 2103701 [UW/Denolle], OAC-CSSI 2103741 [Columbia/Waldhauser], OAC-CSSI 2103494 [TACC/Wang]
SCOPED: Seismic COmputational Platform for Empowering Discovery [Year 2]
This poster was presented at the NSF CSSI annual PI meeting in Houston, September 26-27, 2023. This summarizes the Year 2 efforts of the SCOPED project.</p
Initial results from the InSight mission on Mars
Initial results from the InSight mission on Mars, getting information on the interior of Mars
A Multicentered Study on Epidemiologic and Clinical Characteristics of 37 Neonates With Community-acquired COVID-19
Background: Coronavirus disease 2019 (COVID-19) primarily affects adults and spares children, whereas very little is known about neonates. We tried to define the clinical characteristics, risk factors, laboratory, and imagining results of neonates with community-acquired COVID-19. Methods: This prospective multicentered cohort study included 24 neonatal intensive care units around Turkey, wherein outpatient neonates with COVID-19 were registered in an online national database. Full-term and premature neonates diagnosed with COVID-19 were included in the study, whether hospitalized or followed up as ambulatory patients. Neonates without severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) via reverse transcriptase-polymerase chain reaction testing or whose mothers had been diagnosed with COVID-19 during pregnancy were excluded. Results: Thirty-seven symptomatic neonates were included. The most frequent findings were fever, hypoxemia, and cough (49%, 41%, 27%, respectively). Oxygen administration (41%) and noninvasive ventilation (16%) were frequently required; however, mechanical ventilation (3%) was rarely needed. Median hospitalization was 11 days (1-35 days). One patient with Down syndrome and congenital cardiovascular disorders died in the study period. C-reactive protein (CRP) and prothrombin time (PT) levels were found to be higher in patients who needed supplemental oxygen (0.9 [0.1-8.6] vs. 5.8 [0.3-69.2]p= 0.002, 11.9 [10.1-17.2] vs. 15.2 [11.7-18.0]p= 0.01, respectively) or who were severe/critical (1.0 [0.01-8.6] vs. 4.5 [0.1-69.2]p= 0.01, 11.7 [10.1-13.9] vs. 15.0 [11.7-18.0]p= 0.001, respectively). Conclusions: Symptomatic neonates with COVID-19 had high rates of respiratory support requirements. High CRP levels or a greater PT should alert the physician to more severe disease