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  • 04.06. Seismology  (20)
  • Astronomy
  • J24
  • J31
  • Lunar and Planetary Science and Exploration
  • Q11
  • 2015-2019  (25)
  • 1
    Publication Date: 2019-07-12
    Description: In the last 100 years, the global population has more than quadrupled to over seven billion people. At the same time, the demand for food and standard of living has been increasing which has amplified the global water use by nearly eight times from approximately 500 to 4000 cu km per yr from 1900 to 2010. With the increasing concern to sustain the growing population on Earth it is necessary to seek other approaches to ensure that our planet will have resources for generations to come. In recent years, the advancement of space travel and technology has allowed the idea of mining asteroids with resources closer to becoming a reality. During the duration of the internship at NASA Kennedy Space Center, several geotechnical tests were conducted on BP-1 lunar simulant and asteroid simulant Orgueil. The tests that were conducted on BP-1 was to practice utilizing the equipment that will be used on the asteroid simulant and the data from those tests will be omitted from report. Understanding the soil mechanics of asteroid simulant Orgueil will help provide basis for future technological advances and prepare scientists for the conditions they may encounter when mining asteroids becomes reality in the distant future. Distinct tests were conducted to determine grain size distribution, unconsolidated density, and maximum density. Once the basic properties are known, the asteroid simulant will be altered to different levels of compaction using a vibrator table to see how compaction affects the density. After different intervals of vibration compaction, a miniature vane shear test will be conducted. Laboratory vane shear testing is a reliable tool to investigate strength anisotropy in the vertical and horizontal directions of a very soft to stiff saturated fine-grained clayey soil. This test will provide us with a rapid determination of the shear strength on the undisturbed compacted regolith. The results of these tests will shed light on how much torque is necessary to drill through the surface of an asteroid. Most of the known asteroids are believed to be left over material during the formation of the solar system that never accreted to form planets. Asteroids can be found in several groups such as Trojan Asteroids, Near Earth Asteroids (NEAs) and the main asteroid belt. The Trojan Asteroids orbit the 4th and 5th Lagrange points of major planets in the Solar System while the NEA's have orbits that are close to and sometimes intersect with Earths orbit and the Main Asteroid Belt which is found between the orbit of Mars and Jupiter. Gravitational perturbations can alter the orbit of asteroids in the Main Asteroid Belt causing them to move closer to earth causing them to become in the NEA class.
    Keywords: Lunar and Planetary Science and Exploration
    Type: KSC-E-DAA-TN42077
    Format: application/pdf
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  • 2
    Publication Date: 2020-01-04
    Description: The Origins, Spectral Interpretation, Resource Identification, and Security Regolith Explorer(OSIRISREx) mission observed the The Origins, Spectral Interpretation, Resource Identification, and SecurityRegolith Explorer (OSIRISREx) mission observed the Moon during the spacecraft's Earth gravity assist in 2017. From the spacecraft view, the lunar phase was 42, and the inview hemisphere was dominated by anorthositic highlands terrain. Lunar spectra obtained by the OSIRISREx Visible and InfraRed Spectrometer show evidence of several candidate absorption features. We observe the 2.8m hydration band, confirming the spectral results from other missions, but detected in fulldisk spectra. We also tentatively identify weak spectral features near 0.9 and 1.3 m, consistent with lunar regolith containing a mixture of plagioclase and orthopyroxene minerals, as expected for highlands terrain.
    Keywords: Lunar and Planetary Science and Exploration
    Type: GSFC-E-DAA-TN76610 , Geophysical Research Letters (ISSN 0094-8276) (e-ISSN 1944-8007); 46; 12; 6322-6326
    Format: text
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  • 3
    Publication Date: 2019-07-13
    Description: This paper presents the Orion Exploration Mission 1 Linear Covariance Analysis for the DRO mission using ground-based navigation. The Delta V statistics for each maneuver are presented. In particular, the statistics of the lunar encounters and the Entry Interface are presented.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JSC-CN-35077 , AAS/AIAA Space Flight Mechanics Meeting; Feb 14, 2016 - Feb 18, 2016; Napa, CA; United States
    Format: application/pdf
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  • 4
    Publication Date: 2019-07-13
    Description: We report the design of a new application-specific integrated circuit (ASIC) for use in radio telescope correlators. It supports the construction of correlators for an arbitrarily large number of signals. The ASIC uses an intrinsically low-power architecture along with design techniques and a process that together result in unprecedentedly low power consumption. The design is flexible in that it can support telescopes with almost any number of antennas N. It is intended for use in an "FX" correlator, where a uniform filter bank breaks each signal into separate frequency channels prior to correlation.
    Keywords: Astronomy
    Type: United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM); Jan 06, 2016 - Jan 09, 2016; Boulder, CO; United States
    Format: text
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  • 5
    Publication Date: 2019-08-26
    Description: Radio telescopes that employ arrays of many antennas are in operation, and ever larger ones are being designed and proposed. Signals from the antennas are combined by cross-correlation. While the cost of most components of the telescope is proportional to the number of antennas N, the cost and power consumption of cross-correlationare proportional to N2 and dominate at sufficiently large N. Here we report the design of an integrated circuit (IC) that performs digital cross-correlations for arbitrarily many antennas in a power-efficient way. It uses an intrinsically low-power architecture in which the movement of data between devices is minimized. In a large system, each IC performs correlations for all pairs of antennas but for a portion of the telescope's bandwidth (the so-called "FX" structure). In our design, the correlations are performed in an array of 4096 complex multiply-accumulate (CMAC) units. This is sufficient to perform all correlations in parallel for 64 signals (N=32 antennas with 2 opposite-polarization signals per antenna). When N is larger, the input data are buffered in an on-chipmemory and the CMACs are re-used as many times as needed to compute all correlations. The design has been synthesized and simulated so as to obtain accurate estimates of the IC's size and power consumption. It isintended for fabrication in a 32 nm silicon-on-insulator process, where it will require less than 12mm2 of silicon area and achieve an energy efficiency of 1.76 to 3.3 pJ per CMAC operation, depending on the number of antennas. Operation has been analyzed in detail up to N = 4096. The system-level energy efficiency, including board-levelI/O, power supplies, and controls, is expected to be 5 to 7 pJ per CMAC operation. Existing correlators for the JVLA (N = 32) and ALMA (N = 64) telescopes achieve about 5000 pJ and 1000 pJ respectively usingapplication-specific ICs in older technologies. To our knowledge, the largest-N existing correlator is LEDA atN = 256; it uses GPUs built in 28 nm technology and achieves about 1000 pJ. Correlators being designed for the SKA telescopes (N = 128 and N = 512) using FPGAs in 16nm technology are predicted to achieve about 100 pJ.
    Keywords: Astronomy
    Type: Journal of Astronomical Instrumentation; 5; 2; 1650002
    Format: text
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  • 6
    Publication Date: 2018-03-23
    Description: The 24 August 2016 earthquake very heavily struck the central sector of the Apennines among the Lazio,Umbria, Marche and Abruzzi regions, devastating the town of Amatrice, the nearby villages and other localities along the Tronto valley. In this paper we present the results of the macroseismic field survey carried out using the European Macroseismic Scale (EMS) to take the heterogeneity of the building stock into account. We focused on the epicentral area, where geological conditions may also have contributed to the severity of damage. On the whole, we investigated 143 localities; the maximum intensity 10 EMS has been estimated for Amatrice, Pescara del Tronto and some villages in between. The severely damaged area (8-9 EMS) covers a strip trending broadly N-S and extending 15 km in length and 5 km in width; minor damage occurred over an area up to 35 km northward from the epicenter.
    Description: Published
    Description: 3T. Storia Sismica
    Description: 4T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: 1IT. Reti di monitoraggio
    Description: 4IT. Banche dati
    Description: JCR Journal
    Keywords: Macroseismic survey ; EMS intensity ; Amatrice 2016 earthquake ; 04.06. Seismology ; 05.02. Data dissemination
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 7
    Publication Date: 2020-12-03
    Description: We present the first high-quality catalog of early aftershocks of the three mainshocks of the 2016 central Italy Amatrice-Visso-Norcia normal faulting sequence. We located 10,574 manually picked aftershocks with a robust probabilistic, non-linear method achieving a significant improvement in the solution accuracy and magnitude completeness with respect to previous studies. Aftershock distribution and relocated mainshocks give insight into the complex architecture of major causative and subsidiary faults, thus providing crucial constraints on multi-segment rupture models. We document reactivation and kinematic inversion of a WNW-dipping listric structure, referable to the inherited Mts Sibillini Thrust (MST) that controlled segmentation of the causative normal faults. Spatial partitioning of aftershocks evidences that the MST lateral ramp had a dual control on rupture propagation, behaving as a barrier for the Amatrice and Visso mainshocks, and later as an asperity for the Norcia mainshock. We hypothesize that the Visso mainshock re-activated also the deep part of an optimally oriented preexisting thrust. Aftershock patterns reveal that the Amatrice Mw5.4 aftershock and the Norcia mainshock ruptured two distinct antithetic faults 3-4 km apart. Therefore, our results suggest to consider both the MST cross structure and the subsidiary antithetic fault in the finite-fault source modelling of the Norcia earthquake.
    Description: Published
    Description: 6921
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: 2016 Amatrice-Visso-Norcia seismic sequence (central Italy) ; high-quality catalog of early Aftershocks ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
    Publication Date: 2021-03-04
    Description: The ground-motion median and standard deviation of empirical groundmotion prediction equations (GMPEs) are usually poorly constrained in the nearsource region due to the general lack of strong-motion records. Here we explore the use of a deterministic–stochastic simulation technique, specifically tailored to reproduce directivity effects, to evaluate the expected ground motion and its variability at a near-source site, and seek a strategy to overcome the known GMPEs limitations. To this end, we simulated a large number of equally likely scenario events for three earthquake magnitudes (Mw 7.0, 6.0, and 5.0) and various source-to-site distances. The variability of the explored synthetic ground motion is heteroscedastic, with smaller values for larger earthquakes. The standard deviation is comparable with empirical estimates for smaller events and reduces by 30%–40% for stronger earthquakes. We then illustrate how to incorporate directivity effects into probabilistic seismichazard analysis (PSHA). This goal is pursued by calibrating a set of synthetic GMPEs and reducing their aleatory variability (∼50%) by including a predictive directivity term that depends on the apparent stress parameter obtained through the simulation method. Our results show that, for specific source-to-site configurations, the nonergodic PSHA is very sensitive to the additional epistemic uncertainty that may augment the exceedance probabilities when directivity effects are maximized. The proposed approach may represent a suitable way to compute more accurate hazard estimates.
    Description: This work was supported by the project MASSIMO—Cultural Heritage Monitoring in Seismic Area, PON01/02710—coordinated by Istituto Nazionale di Geofisica e Vulcanologia (INGV) and funded by the Italian Ministry of Education, University and Research and by the Seismic Hazard Center of Istituto Nazionale di Geofisica e Vulcanologia (Centro per la Pericolosità Sismica [CPS]).
    Description: Published
    Description: 966-983
    Description: 5T. Modelli di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: seismogenic sources ; finite fault simulations ; near source ; directivity effects ; ground motion variability ; seismic hazard ; Southern Italy ; 04.06. Seismology ; 05.06. Methods
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 9
    Publication Date: 2021-07-14
    Description: This paper describes the model implementation and presents results of a probabilistic seismic hazard assess- ment (PSHA) for the Mt. Etna volcanic region in Sicily, Italy, considering local volcano-tectonic earthquakes. Working in a volcanic region presents new challenges not typically faced in standard PSHA, which are broadly due to the nature of the local volcano-tectonic earthquakes, the cone shape of the volcano and the attenuation properties of seismic waves in the volcanic region. These have been accounted for through the development of a seismic source model that integrates data from different disciplines (historical and instrumental earthquake datasets, tectonic data, etc.; presented in Part 1, by Azzaro et al., 2017) and through the development and software implementation of original tools for the computa- tion, such as a new ground-motion prediction equation and magnitude–scaling relationship specifically derived for this volcanic area, and the capability to account for the surfi- cial topography in the hazard calculation, which influences source-to-site distances. Hazard calculations have been car- ried out after updating the most recent releases of two widely used PSHA software packages (CRISIS, as in Ordaz et al., 2013; the OpenQuake engine, as in Pagani et al., 2014). Re- sults are computed for short- to mid-term exposure times (10% probability of exceedance in 5 and 30 years, Poisson and time dependent) and spectral amplitudes of engineer- ing interest. A preliminary exploration of the impact of site- specific response is also presented for the densely inhabited Etna’s eastern flank, and the change in expected ground mo- tion is finally commented on. These results do not account for M 〉 6 regional seismogenic sources which control the hazard at long return periods. However, by focusing on the impact of M 〈 6 local volcano-tectonic earthquakes, which dominate the hazard at the short- to mid-term exposure times considered in this study, we present a different viewpoint that, in our opinion, is relevant for retrofitting the existing buildings and for driving impending interventions of risk re- duction.
    Description: Published
    Description: 1999–2015
    Description: 5T. Modelli di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: Mt. Etna, Seismic Hazard, GMPE ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 10
    Publication Date: 2019-05-06
    Description: Il 24 agosto 2016 un terremoto di magnitudo 6.0 ha dato inizio ad una sequenza sismica in Italia centrale, che ha generato decine di migliaia di eventi sismicitra cui un evento Mw=6.5 il 30 ottobre. Per l’analisi elarevisione di questa sequenza si rimanda ad unauscitaspeciale del BSI previstanei primi mesi del 2019(S_BSI_CI). In questo quadrimestre,così come nel precedente e nei successivi,gli eventi nella zona della sequenza (rettangolo in mappa; lat=42.2-43.2, lon=12.4-14.1) sono quelli localizzati nella sala di sorveglianza. Solo gli eventi con M〉=3.5, e pochi altri (vedi Marchetti et al.,Annals of Geophys. DOI: 10.4401/ag-7169) sono stati rivisti.
    Description: Istituto Nazionale di Geofisica - Dipartimento di Protezione Civile
    Description: Published
    Description: 4IT. Banche dati
    Keywords: Bollettino Sismico Italiano ; gennaio–aprile 2017 ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: report
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