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  • 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous  (22)
  • Climate change  (16)
  • Ecosystem ecology
  • Seismological Society of America  (20)
  • John Wiley & Sons  (16)
  • American Institute of Physics (AIP)
  • Nature Publishing Group
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Years
  • 1
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Animal Ecology 87 (2018): 906-920, doi:10.1111/1365-2656.12827.
    Description: Recent studies unravelled the effect of climate changes on populations through their impact on functional traits and demographic rates in terrestrial and freshwater ecosystems, but such understanding in marine ecosystems remains incomplete. Here, we evaluate the impact of the combined effects of climate and functional traits on population dynamics of a long‐lived migratory seabird breeding in the southern ocean: the black‐browed albatross (Thalassarche melanophris, BBA). We address the following prospective question: “Of all the changes in the climate and functional traits, which would produce the biggest impact on the BBA population growth rate?” We develop a structured matrix population model that includes the effect of climate and functional traits on the complete BBA life cycle. A detailed sensitivity analysis is conducted to understand the main pathway by which climate and functional trait changes affect the population growth rate. The population growth rate of BBA is driven by the combined effects of climate over various seasons and multiple functional traits with carry‐over effects across seasons on demographic processes. Changes in sea surface temperature (SST) during late winter cause the biggest changes in the population growth rate, through their effect on juvenile survival. Adults appeared to respond to changes in winter climate conditions by adapting their migratory schedule rather than by modifying their at‐sea foraging activity. However, the sensitivity of the population growth rate to SST affecting BBA migratory schedule is small. BBA foraging activity during the pre‐breeding period has the biggest impact on population growth rate among functional traits. Finally, changes in SST during the breeding season have little effect on the population growth rate. These results highlight the importance of early life histories and carry‐over effects of climate and functional traits on demographic rates across multiple seasons in population response to climate change. Robust conclusions about the roles of various phases of the life cycle and functional traits in population response to climate change rely on an understanding of the relationships of traits to demographic rates across the complete life cycle.
    Description: NSF Grant Number: OPP‐1246407; European Research Council Advanced Grant Grant Numbers: ERC‐2012‐ADG_20120314, 322989
    Keywords: Birds ; Climate change ; Foraging behaviours ; Non‐breeding season ; Phenotypic traits ; Pre‐breeding season ; Timing of breeding ; Wing length
    Repository Name: Woods Hole Open Access Server
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  • 2
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecosphere 8 (2017): 10.1002/ecs2.2017, doi:10.1002/ecs2.2017.
    Description: Historically low temperatures have severely limited skeleton-breaking predation on the Antarctic shelf, facilitating the evolution of a benthic fauna poorly defended against durophagy. Now, rapid warming of the Southern Ocean is restructuring Antarctic marine ecosystems as conditions become favorable for range expansions. Populations of the lithodid crab Paralomis birsteini currently inhabit some areas of the continental slope off Antarctica. They could potentially expand along the slope and upward to the outer continental shelf, where temperatures are no longer prohibitively low. We identified two sites inhabited by different densities of lithodids in the slope environment along the western Antarctic Peninsula. Analysis of the gut contents of P. birsteini trapped on the slope revealed them to be opportunistic invertivores. The abundances of three commonly eaten, eurybathic taxa—ophiuroids, echinoids, and gastropods—were negatively associated with P. birsteini off Marguerite Bay, where lithodid densities averaged 4280 ind/km2 at depths of 1100–1499 m (range 3440–5010 ind/km2), but not off Anvers Island, where lithodid densities were lower, averaging 2060 ind/km2 at these depths (range 660–3270 ind/km2). Higher abundances of lithodids appear to exert a negative effect on invertebrate distribution on the slope. Lateral or vertical range expansions of P. birsteini at sufficient densities could substantially reduce populations of their benthic prey off Antarctica, potentially exacerbating the direct impacts of rising temperatures on the distribution and diversity of the contemporary shelf benthos.
    Description: Division of Polar Programs Grant Numbers: ANT-0838466, ANT-0838844, ANT-1141877, ANT-1141896; Vetenskapsrådet Grant Number: 824-2008-6429; H2020 Marie Skłodowska-Curie Actions Grant Number: 704895; U.S. National Science Foundation; European Commission; University of Alabama at Birmingham
    Keywords: Antarctica ; Bathyal ; Benthic ; Climate change ; Echinoidea ; Lithodidae ; Ophiuroidea ; Paralomis ; Polar emergence ; Predation
    Repository Name: Woods Hole Open Access Server
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  • 3
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 9387–9398, doi:10.1002/2017JC012949.
    Description: Sea surface temperatures of the northwest Atlantic have warmed dramatically over the last several decades, while benthic temperatures have increased at a slower pace. Here we analyze a subset of the CMIP5 global Earth system model ensemble using a statistical downscaling approach to determine potential future changes in benthic temperatures on the northwest Atlantic continental shelf and slope (〈500 m). We put future changes in the context of possible impacts of ocean warming on the high-value, wild-caught American Lobster (Homarus americanus) fishery. Future bottom temperatures of the northwest Atlantic under a business-as-usual (RCP8.5) and a climate-policy (RCP4.5) scenario are projected to increase by 0–1.5°C and 1.2–2.4°C by 2050 and 0–1.9°C and 2.3–4.3°C by the end of the century for RCP4.5 and RCP8.5, respectively. H. americanus experiences thermal stress at temperatures above 20°C, and projected increases in temperature is likely to result in changes in the distribution of optimal thermal egg hatching and settlement indicators. Inshore regions of southern New England, where H. americanus biomass and catch have been declining historically, will likely become inhospitable under either future scenario, while thermal egg hatching and settlement indicators will expand offshore and in the Gulf of Maine. These changes imply that members of the fishery based in southern New England may need to recapitalize to larger vessels to prepare for potential changes brought on by future climate warming. Results from the downscaling presented here can be useful in preparing for potential changes to other fisheries or in future climate vulnerability analyses.
    Description: John D. and Catherine T. MacArthur Foundation Grant Number: 14-106159-000-CFP; NASA Grant Number: NNX14AP62A; “National Marine Sanctuaries as Sentinel Sites for a Demonstration Marine Biodiversity Observation Network (MBON)”; National Ocean Partnership Program Grant Number: NOPP RFP NOAA-NOS IOOS-2014-2003803; NOAA Integrated Ocean Observing System (IOOS) Program Office
    Keywords: Benthic temperature ; Climate change ; Warming ; American Lobster
    Repository Name: Woods Hole Open Access Server
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  • 4
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 9399–9414, doi:10.1002/2017JC012953.
    Description: The U.S. Northeast Continental Shelf is experiencing rapid warming, with potentially profound consequences to marine ecosystems. While satellites document multiple scales of spatial and temporal variability on the surface, our understanding of the status, trends, and drivers of the benthic environmental change remains limited. We interpolated sparse benthic temperature data along the New England Shelf and upper Slope using a seasonally dynamic, regionally specific multiple linear regression model that merged in situ and remote sensing data. The statistical model predicted nearly 90% of the variability of the data, resulting in a synoptic time series spanning over three decades from 1982 to 2014. Benthic temperatures increased throughout the domain, including in the Gulf of Maine. Rates of benthic warming ranged from 0.1 to 0.4°C per decade, with fastest rates occurring in shallow, nearshore regions and on Georges Bank, the latter exceeding rates observed in the surface. Rates of benthic warming were up to 1.6 times faster in winter than the rest of the year in many regions, with important implications for disease occurrence and energetics of overwintering species. Drivers of warming varied over the domain. In southern New England and the mid-Atlantic shallow Shelf regions, benthic warming was tightly coupled to changes in SST, whereas both regional and basin-scale changes in ocean circulation affect temperatures in the Gulf of Maine, the Continental Shelf, and Georges Banks. These results highlight data gaps, the current feasibility of prediction from remotely sensed variables, and the need for improved understanding on how climate may affect seasonally specific ecological processes.
    Description: John D. and Catherine T. MacArthur Foundation Grant Number: 14–106159-000-CFP; National Aeronautics and Space Administration Grant Number: NNX14AP62A
    Keywords: Benthic habitat ; New England ; Warming ; Climate change ; Satellite remote sensing
    Repository Name: Woods Hole Open Access Server
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  • 5
    Publication Date: 2022-05-25
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecology and Evolution 7 (2017): 2449–2460, doi:10.1002/ece3.2863.
    Description: Rapid environmental change at high latitudes is predicted to greatly alter the diversity, structure, and function of plant communities, resulting in changes in the pools and fluxes of nutrients. In Arctic tundra, increased nitrogen (N) and phosphorus (P) availability accompanying warming is known to impact plant diversity and ecosystem function; however, to date, most studies examining Arctic nutrient enrichment focus on the impact of relatively large (〉25x estimated naturally occurring N enrichment) doses of nutrients on plant community composition and net primary productivity. To understand the impacts of Arctic nutrient enrichment, we examined plant community composition and the capacity for ecosystem function (net ecosystem exchange, ecosystem respiration, and gross primary production) across a gradient of experimental N and P addition expected to more closely approximate warming-induced fertilization. In addition, we compared our measured ecosystem CO2 flux data to a widely used Arctic ecosystem exchange model to investigate the ability to predict the capacity for CO2 exchange with nutrient addition. We observed declines in abundance-weighted plant diversity at low levels of nutrient enrichment, but species richness and the capacity for ecosystem carbon uptake did not change until the highest level of fertilization. When we compared our measured data to the model, we found that the model explained roughly 30%–50% of the variance in the observed data, depending on the flux variable, and the relationship weakened at high levels of enrichment. Our results suggest that while a relatively small amount of nutrient enrichment impacts plant diversity, only relatively large levels of fertilization—over an order of magnitude or more than warming-induced rates—significantly alter the capacity for tundra CO2 exchange. Overall, our findings highlight the value of measuring and modeling the impacts of a nutrient enrichment gradient, as warming-related nutrient availability may impact ecosystems differently than single-level fertilization experiments.
    Description: NASA Terrestrial Ecology Grant Number: NNX12AK83G; National Science Foundation Division of Graduate Education Grant Number: DGE-11-44155
    Keywords: Arctic ; Climate change ; Ecosystem function ; Ecosystem respiration ; Gross primary productivity ; Net ecosystem ; CO2 exchange ; Plant diversity
    Repository Name: Woods Hole Open Access Server
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  • 6
    Publication Date: 2022-05-25
    Description: Author Posting. © Ecological Society of America, 2017. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecology 98 (2017): 940-951, doi:10.1002/ecy.1749.
    Description: Evidence of climate-change-driven shifts in plant and animal phenology have raised concerns that certain trophic interactions may be increasingly mismatched in time, resulting in declines in reproductive success. Given the constraints imposed by extreme seasonality at high latitudes and the rapid shifts in phenology seen in the Arctic, we would also expect Antarctic species to be highly vulnerable to climate-change-driven phenological mismatches with their environment. However, few studies have assessed the impacts of phenological change in Antarctica. Using the largest database of phytoplankton phenology, sea-ice phenology, and Adélie Penguin breeding phenology and breeding success assembled to date, we find that, while a temporal match between Penguin breeding phenology and optimal environmental conditions sets an upper limit on breeding success, only a weak relationship to the mean exists. Despite previous work suggesting that divergent trends in Adélie Penguin breeding phenology are apparent across the Antarctic continent, we find no such trends. Furthermore, we find no trend in the magnitude of phenological mismatch, suggesting that mismatch is driven by interannual variability in environmental conditions rather than climate-change-driven trends, as observed in other systems. We propose several criteria necessary for a species to experience a strong climate-change-driven phenological mismatch, of which several may be violated by this system.
    Description: Funding to H. J. Lynch and C. Youngflesh was provided by the National Science Foundation Grant OPP/GSS 1255058, to S. Jenouvrier, H. J. Lynch, C. Youngflesh, Y. Li, and R. Ji by the National Science Foundation Grant 1341474, to S. Jenouvrier, Y. Li, and R. Ji by NASA grant NNX14AH74G, to D. G. Ainley, G. Ballard, and K. M. Dugger by the National Science Foundation Grants OPP 9526865, 9814882, 0125608, 0944411 and 0440643, to P. O’B. Lyver by New Zealand’s Ministry of Business, Innovation, and Employment Grants C09X0510 and C01X1001, and Ministry of Primary Industry grants with logistic support from Antarctica New Zealand.
    Keywords: Anna Karenina Principle ; Antarctica ; Asynchrony ; Bayesian hierarchical model ; Climate change ; Phenology ; Pygoscelis adeliae ; Quantile regression
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  • 7
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 17 (2016): 4333–4353, doi:10.1002/2016GC006582.
    Description: Borehole logging data from legacy wells directly constrain the contemporary distribution of subsea permafrost in the sedimentary section at discrete locations on the U.S. Beaufort Margin and complement recent regional analyses of exploration seismic data to delineate the permafrost's offshore extent. Most usable borehole data were acquired on a ∼500 km stretch of the margin and within 30 km of the contemporary coastline from north of Lake Teshekpuk to nearly the U.S.-Canada border. Relying primarily on deep resistivity logs that should be largely unaffected by drilling fluids and hole conditions, the analysis reveals the persistence of several hundred vertical meters of ice-bonded permafrost in nearshore wells near Prudhoe Bay and Foggy Island Bay, with less permafrost detected to the east and west. Permafrost is inferred beneath many barrier islands and in some nearshore and lagoonal (back-barrier) wells. The analysis of borehole logs confirms the offshore pattern of ice-bearing subsea permafrost distribution determined based on regional seismic analyses and reveals that ice content generally diminishes with distance from the coastline. Lacking better well distribution, it is not possible to determine the absolute seaward extent of ice-bearing permafrost, nor the distribution of permafrost beneath the present-day continental shelf at the end of the Pleistocene. However, the recovery of gas hydrate from an outer shelf well (Belcher) and previous delineation of a log signature possibly indicating gas hydrate in an inner shelf well (Hammerhead 2) imply that permafrost may once have extended across much of the shelf offshore Camden Bay.
    Description: 2017-05-04
    Keywords: Permafrost ; Arctic Ocean ; Climate change ; Borehole logging ; Gas hydrates
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  • 8
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 31 (2017): 96–113, doi:10.1002/2016GB005374.
    Description: Using the Community Earth System Model, we explore the role of human land use and land cover change (LULCC) in modifying the terrestrial carbon budget in simulations forced by Representative Concentration Pathway 8.5, extended to year 2300. Overall, conversion of land (e.g., from forest to croplands via deforestation) results in a model-estimated, cumulative carbon loss of 490 Pg C between 1850 and 2300, larger than the 230 Pg C loss of carbon caused by climate change over this same interval. The LULCC carbon loss is a combination of a direct loss at the time of conversion and an indirect loss from the reduction of potential terrestrial carbon sinks. Approximately 40% of the carbon loss associated with LULCC in the simulations arises from direct human modification of the land surface; the remaining 60% is an indirect consequence of the loss of potential natural carbon sinks. Because of the multicentury carbon cycle legacy of current land use decisions, a globally averaged amplification factor of 2.6 must be applied to 2015 land use carbon losses to adjust for indirect effects. This estimate is 30% higher when considering the carbon cycle evolution after 2100. Most of the terrestrial uptake of anthropogenic carbon in the model occurs from the influence of rising atmospheric CO2 on photosynthesis in trees, and thus, model-projected carbon feedbacks are especially sensitive to deforestation.
    Description: National Science Foundation Grant Numbers: AGS 1049033, CCF-1522054
    Description: 2017-07-23
    Keywords: Carbon cycle ; Climate change ; Land use and land cover change ; Earth system models
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  • 9
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 8208–8224, doi:10.1002/2017JC012985.
    Description: Estimates of the global ocean vertical velocities (Eulerian, eddy-induced, and residual) from a dynamically consistent and data-constrained ocean state estimate are presented and analyzed. Conventional patterns of vertical velocity, Ekman pumping, appear in the upper ocean, with topographic dominance at depth. Intense and vertically coherent upwelling and downwelling occur in the Southern Ocean, which are likely due to the interaction of the Antarctic Circumpolar Current and large-scale topographic features and are generally canceled out in the conventional zonally averaged results. These “elevators” at high latitudes connect the upper to the deep and abyssal oceans and working together with isopycnal mixing are likely a mechanism, in addition to the formation of deep and abyssal waters, for fast responses of the deep and abyssal oceans to the changing climate. Also, Eulerian and parameterized eddy-induced components are of opposite signs in numerous regions around the global ocean, particularly in the ocean interior away from surface and bottom. Nevertheless, residual vertical velocity is primarily determined by the Eulerian component, and related to winds and large-scale topographic features. The current estimates of vertical velocities can serve as a useful reference for investigating the vertical exchange of ocean properties and tracers, and its complex spatial structure ultimately permits regional tests of basic oceanographic concepts such as Sverdrup balance and coastal upwelling/downwelling.
    Description: National Science Foundation Grant Numbers: OCE-1736633 , OCE-1534618 , OCE-0961713; National Oceanic and Atmospheric Administration Grant Number: NA10OAR4310135
    Description: 2018-04-27
    Keywords: Vertical velocity ; Vertical transport ; Vertical exchange ; Ocean state estimate ; Climate change ; Southern Ocean
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  • 10
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 121 (2016): 1476–1501, doi:10.1002/2015JC011449.
    Description: A new planktonic ecosystem model was constructed for the Eastern Bering Sea based on observations from the 2007–2010 BEST/BSIERP (Bering Ecosystem Study/Bering Sea Integrated Ecosystem Research Program) field program. When run with forcing from a data-assimilative ice-ocean hindcast of 1971–2012, the model performs well against observations of spring bloom time evolution (phytoplankton and microzooplankton biomass, growth and grazing rates, and ratios among new, regenerated, and export production). On the southern middle shelf (57°N, station M2), the model replicates the generally inverse relationship between ice-retreat timing and spring bloom timing known from observations, and the simpler direct relationship between the two that has been observed on the northern middle shelf (62°N, station M8). The relationship between simulated mean primary production and mean temperature in spring (15 February to 15 July) is generally positive, although this was found to be an indirect relationship which does not continue to apply across a future projection of temperature and ice cover in the 2040s. At M2, the leading direct controls on total spring primary production are found to be advective and turbulent nutrient supply, suggesting that mesoscale, wind-driven processes—advective transport and storminess—may be crucial to long-term trends in spring primary production in the southeastern Bering Sea, with temperature and ice cover playing only indirect roles. Sensitivity experiments suggest that direct dependence of planktonic growth and metabolic rates on temperature is less significant overall than the other drivers correlated with temperature described above.
    Description: This work was supported by the National Science Foundation through grants ARC-1107187, ARC-1107303, and ARC-1107588, for BEST Synthesis, and PLR-1417365.
    Description: 2016-08-20
    Keywords: Phytoplankton bloom ; Climate change ; Bering Sea ; Microzooplankton ; Ecosystem model ; Phenology
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  • 11
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 121 (2016): 6137-6158, doi:10.1002/2016JC011784.
    Description: Early ice retreat and ocean warming are changing various facets of the Arctic marine ecosystem, including the biogeographic distribution of marine organisms. Here an endemic copepod species, Calanus glacialis, was used as a model organism, to understand how and why Arctic marine environmental changes may induce biogeographic boundary shifts. A copepod individual-based model was coupled to an ice-ocean-ecosystem model to simulate temperature- and food-dependent copepod life history development. Numerical experiments were conducted for two contrasting years: a relatively cold and normal sea ice year (2001) and a well-known warm year with early ice retreat (2007). Model results agreed with commonly known biogeographic distributions of C. glacialis, which is a shelf/slope species and cannot colonize the vast majority of the central Arctic basins. Individuals along the northern boundaries of this species' distribution were most susceptible to reproduction timing and early food availability (released sea ice algae). In the Beaufort, Chukchi, East Siberian, and Laptev Seas where severe ocean warming and loss of sea ice occurred in summer 2007, relatively early ice retreat, elevated ocean temperature (about 1–2°C higher than 2001), increased phytoplankton food, and prolonged growth season created favorable conditions for C. glacialis development and caused a remarkable poleward expansion of its distribution. From a pan-Arctic perspective, despite the great heterogeneity in the temperature and food regimes, common biogeographic zones were identified from model simulations, thus allowing a better characterization of habitats and prediction of potential future biogeographic boundary shifts.
    Description: National Science Foundation Polar Programs Grant Number: (PLR-1417677, PLR-1417339, and PLR-1416920)
    Description: 2017-02-20
    Keywords: Arctic Ocean ; Marine ecosystem ; Climate change ; Biogeography ; Individual-based model ; C. glacialis
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  • 12
    Publication Date: 2021-02-10
    Description: Heki (2011) and Heki and Enomoto (2013) claimed that anomalous, yet similar, increases of ionospheric total electron content (TEC) started ~40 min prior to the 2011 Tohoku-Oki, as well as before other Mw〉8 earthquakes. The authors concluded that the reported TEC anomalies were likely related to the pending earthquakes, suggesting also that TEC monitoring may be useful for future earthquake prediction. Here we carefully examine the findings of Heki (2011) and Heki and Enomoto (2013) by performing new analyses of the same TEC data. Our interpretation is that the 40 min onset of the ionospheric precursors is an artifact induced by the definition of the reference line adopted in analyzing TEC variations. We also discuss this repeatability in the tectonic and geodynamic context of the earthquakes. By performing a Superimposed Epoch Analysis of TEC data, we show that, however, the TEC increase reported by Heki (2011) was not particularly anomalous. We conclude that the TEC precursors reported by Heki (2011) and Heki and Enomoto (2013) are not useful for developing short-term earthquake prediction capabilities.
    Description: Published
    Description: 1383–1393
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Ionosphere ; Total Electron Content ; Earthquake precursors ; Short-term earthquake prediction ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous ; 01. Atmosphere::01.03. Magnetosphere::01.03.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
    Publication Date: 2017-04-04
    Description: Earthquake-rotated objects (EROs) have been observed and described for centuries (e.g., Hoffmann, 1838; Mallet, 1862; Reid, 1910). Several theories about the rotating mechanisms have been developed. Kozák (2006) classified rotating effects as those caused by a deviation between the projection of the center of gravity into the contact plane and the point of strongest adhesion (Rot1) and those due to subsequent arrival of ground-motion phases from different directions (Rot2). The EROs found in the literature include parts of buildings, such as chimneys, monuments, tombstones, and columns, often described with great care and in detail by early earthquake reports (Mallet, 1862) or still accessible (Boschi et al., 1995). However, in most cases rotational effects are observed on vertically oriented objects such as gravestones, tall monuments, and single columns (Kozák, 2009). Although earthquake- toppled objects (ETOs) allow the determination of minimum ground-motion thresholds which caused the toppling (Kamai and Hatzor 2008; Hinzen, 2010, 2012), EROs and earthquake-deformed objects (EDOs) present the chance to make a more detailed back calculation of the causative ground motion (Yegian et al., 1994; Lee et al., 2009; Hinzen et al., 2010; Hough et al., 2012). Numerous EROs were observed and documented during the 2009 L’Aquila earthquake in central Italy. Cucci and Tertulliani (2011) and Castellano et al. (2012) showed a correlation between the occurrence of EROs in the mesoseismal zone, the fault orientation, and the site conditions. Some of the simply structured and vertically oriented objects mapped by Cucci et al. (2011) and Cucci and Tertulliani (2011) offer the opportunity to use local strong-motion records to test different hypotheses about the mechanisms that caused the rotation. A main question in this context is whether near-field rotational components of ground motion are necessary to rotate the studied objects or whether 3D purely translational ground motions are sufficient to explain the observations. In this study, we use discrete-element models of EROs that are based on laser scans to study the dynamic behavior of the EROs and rotations induced by translation ground motions and uneven foundations.
    Description: Published
    Description: 745-751
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: earthquake rotations ; L'Aquila 2009 earthquake ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
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  • 14
    Publication Date: 2017-04-04
    Description: In the past few years, the awareness that earthquake-induced rotational effects can be significant in the near-fault region of an earthquake, and the consequent implications in seismic engineering, has gained rotational seismology a strong recovery in the attention of the scientific community. Impulses came from direct observations as well as numerical simulations, and special volumes related to this topic have been recently published by the Bulletin of the Seismological Society of America (Lee et al., 2009) and by the Journal of Seismology (Igel et al., 2012). In particular, some of the most recent papers on this subject addressed the earthquake-rotated objects (EROs hereinafter), considering the possible contribution to EROs occurrence from true rotational motion and/or translational motion (Kozák, 2006, 2009; Yang et al., 2010; Hinzen, 2012), the geometry of the structure (Mucciarelli et al., 2011), the clockwise/ counterclockwise (CW/CCW hereinafter) sense of rotation (Yegian et al., 1994), and the geological conditions at the site (Cucci and Tertulliani, 2011; Castellano et al., 2012). The renewed attention to earthquake-induced rotations allowed the collection of a significant dataset of EROs following the Mw 6.3 2009 L’Aquila (Central Italy) event (see Cucci et al., 2011 for a complete description of the dataset); this kind of data collection is a sound starting point for subsequent quantitative analyses of the data. In this paper, we present a newⒺdataset of EROs (available in the electronic supplement to this paper) originated by the Emilia seismic sequence, which occurred in northern Italy in 2012. The main aim of this study is to verify whether and how the distribution of the 2012 EROs is influenced by some geophysical observables (epicentral distance, intensity, directivity, lithology, etc.), in a geomorphological and seismological context completely different from that of 2009 L’Aquila.
    Description: Published
    Description: 973-981
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: earthquake rotations ; Emilia 2012 earthquakes ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
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  • 15
    Publication Date: 2020-02-24
    Description: Accurate earthquake locations are crucial for investigating seismogenic processes, as well as for applications like verifying compliance to the Comprehensive Test Ban Treaty. Earthquake location accuracy is related to the degree of knowledge about the 3-D structure of seismic wave velocity in the Earth. It is well known that modeling errors of calculated travel times may have the effect of shifting the computed epicenters far from the real locations by a distance even larger than the size of the statistical error ellipses, regardless of the accuracy in picking seismic phase arrivals. In the present study, we develop a method of seismic location based on a set of well located events recorded by the dense national seismic network in a seismically active region of central Japan. We show that mislocations of the order of 10-20 km affecting the epicenters calculated from a global seismic network and using the standard IASPEI91 travel times can be effectively removed by applying station-source-specific corrections. The results show a clear correlation of the travel time residuals with the subduction structure beneath Japan.
    Description: Published
    Description: 225-236
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Travel-time correction ; Teleseimic location ; Seismic monitoring and test-ban treaty verification. ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 16
    Publication Date: 2022-05-25
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Earth's Future 3 (2015): 49–65, doi:10.1002/2014EF000274.
    Description: How climate controls hurricane variability has critical implications for society is not well understood. In part, our understanding is hampered by the short and incomplete observational hurricane record. Here we present a synthesis of intense-hurricane activity from the western North Atlantic over the past two millennia, which is supported by a new, exceptionally well-resolved record from Salt Pond, Massachusetts (USA). At Salt Pond, three coarse grained event beds deposited in the historical interval are consistent with severe hurricanes in 1991 (Bob), 1675, and 1635 C.E., and provide modern analogs for 32 other prehistoric event beds. Two intervals of heightened frequency of event bed deposition between 1400 and 1675 C.E. (10 events) and 150 and 1150 C.E. (23 events), represent the local expression of coherent regional patterns in intense-hurricane–induced event beds. Our synthesis indicates that much of the western North Atlantic appears to have been active between 250 and 1150 C.E., with high levels of activity persisting in the Caribbean and Gulf of Mexico until 1400 C.E. This interval was one with relatively warm sea surface temperatures (SSTs) in the main development region (MDR). A shift in activity to the North American east coast occurred ca. 1400 C.E., with more frequent severe hurricane strikes recorded from The Bahamas to New England between 1400 and 1675 C.E. A warm SST anomaly along the western North Atlantic, rather than within the MDR, likely contributed to the later active interval being restricted to the east coast.
    Description: Funding was provided by US National Science Foundation (awards 0903020 and 1356708), the Risk Prediction Initiative at the Bermuda Institute for Ocean Sciences (BIOS), US Department of Energy National Institute for Climate Change Research, National Oceanic and Atmospheric Administration (award NA11OAR431010), and the Dalio Explore Fund.
    Keywords: Tropical cyclones ; Climate change ; Holocene ; Common era ; Sea surface temperature
    Repository Name: Woods Hole Open Access Server
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  • 17
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 120 (2015): 4324–4339, doi:10.1002/2014JC010547.
    Description: In the coastal ocean off the Northeast U.S., the sea surface temperature (SST) in the first half of 2012 was the highest on the record for the past roughly 150 years of recorded observations. The underlying dynamical processes responsible for this extreme event are examined using a numerical model, and the relative contributions of air-sea heat flux versus lateral ocean advective heat flux are quantified. The model accurately reproduces the observed vertical structure and the spatiotemporal characteristics of the thermohaline condition of the Gulf of Maine and the Middle Atlantic Bight waters during the anomalous warming period. Analysis of the model results show that the warming event was primarily driven by the anomalous air-sea heat flux, while the smaller contribution by the ocean advection worked against this flux by acting to cool the shelf. The anomalous air-sea heat flux exhibited a shelf-wide coherence, consistent with the shelf-wide warming pattern, while the ocean advective heat flux was dominated by localized, relatively smaller-scale processes. The anomalous cooling due to advection primarily resulted from the along-shelf heat flux divergence in the Gulf of Maine, while in the Middle Atlantic Bight the advective contribution from the along-shelf and cross-shelf heat flux divergences was comparable. The modeling results confirm the conclusion of the recent analysis of in situ data by Chen et al. (2014a) that the changes in the large-scale atmospheric circulation in the winter of 2011–2012 primarily caused the extreme warm anomaly in the spring of 2012. The effect of along-shelf or cross-shelf ocean advection on the warm anomalies from either the Scotian Shelf or adjacent continental slope was secondary.
    Description: K.C. was supported by the Woods Hole Oceanographic Institution Postdoctoral Scholar program, the Coastal Ocean Institute, and the National Science Foundation (NSF) under grant OCE-1435602. G.G.G. was supported by NSF grants OCE-1435602 and OCE-1129125. Y.-O.K. was supported by the NSF grant OCE-1435602. W.G.Z. was supported by the NSF grant OCE-1129125.
    Description: 2015-12-15
    Keywords: Extreme temperature ; Heat budget ; Northeast U.S. coastal ocean ; Numerical modeling ; Air-sea interaction ; Climate change
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  • 18
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 42 (2015): 831–838, doi:10.1002/2014GL062522.
    Description: Internal waves (IWs) generated in the Luzon Strait propagate into the Northern South China Sea (NSCS), enhancing biological productivity and affecting coral reefs by modulating nutrient concentrations and temperature. Here we use a state-of-the-art ocean data assimilation system to reconstruct water column stratification in the Luzon Strait as a proxy for IW activity in the NSCS and diagnose mechanisms for its variability. Interannual variability of stratification is driven by intrusions of the Kuroshio Current into the Luzon Strait and freshwater fluxes associated with the El Niño–Southern Oscillation. Warming in the upper 100 m of the ocean caused a trend of increasing IW activity since 1900, consistent with global climate model experiments that show stratification in the Luzon Strait increases in response to radiative forcing. IW activity is expected to increase in the NSCS through the 21st century, with implications for mitigating climate change impacts on coastal ecosystems.
    Description: This work was supported by NSF award 1220529 to Anne Cohen, by the Academia Sinica (Taiwan) through a thematic project grant to G.T.F.W. and Anne Cohen, by the Alfred P. Sloan Foundation and the WHOI Oceans and Climate Change Institute/Moltz Fellowship through awards to K.B.K., and by an NSF Graduate Research Fellowship to T.M.D.
    Description: 2015-08-10
    Keywords: Internal waves ; Climate change ; Coral reefs
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  • 19
    Publication Date: 2021-06-25
    Description: We adopt a spectral-element method (SEM) to perform numerical simulations of the complex wavefield generated by the 6 April 2009 Mw 6.3 L’Aquila earthquake in central Italy. The mainshock is represented by a finite-fault solution obtained by inverting strong-motion and Global Positioning System data, testing both 1D and 3D wavespeed models for central Italy. Surface topography, attenuation, and the Moho discontinuity are also accommodated. Including these complexities is essential to accurately simulate seismic-wave propagation. Three-component synthetic waveforms are compared to corresponding velocimeter and strong-motion recordings. The results show a favorable match between data and synthetics up to ∼0:5 Hz in a 200 km × 200 km × 60 km model volume, capturing features mainly related to topography or low-wavespeed basins. We construct synthetic peak ground velocity maps that, for the 3D model, are in good agreement with observations, thus providing valuable information for seismic-hazard assessment. Exploiting the SEM in combination with an adjoint method, we calculate finite-frequency kernels for specific seismic arrivals. These kernels capture the volumetric sensitivity associated with the selected waveform and highlight prominent effects of topography on seismic-wave propagation in central Italy.
    Description: Published
    Description: JCR Journal
    Description: restricted
    Keywords: Wave Propagation ; Earthquake ; Ground Motion ; Basin & Site Effects ; Topographic Effects ; Numerical Modelling ; Spectral-Element Methods ; Adjoint Methods ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 20
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 27 (2013): 1274–1290, doi:10.1002/2013GB004599.
    Description: Here we analyze the impact of projected climate change on plankton ecology in all major ocean biomes over the 21st century, using a multidecade (1880–2090) experiment conducted with the Community Climate System Model (CCSM-3.1) coupled ocean-atmosphere-land-sea ice model. The climate response differs fundamentally in the Northern and Southern Hemispheres for diatom and small phytoplankton biomass and consequently for total biomass, primary, and export production. Increasing vertical stratification in the Northern Hemisphere oceans decreases the nutrient supply to the ocean surface. Resulting decreases in diatom and small phytoplankton biomass together with a relative shift from diatoms to small phytoplankton in the Northern Hemisphere result in decreases in the total primary and export production and export ratio, and a shift to a more oligotrophic, more efficiently recycled, lower biomass euphotic layer. By contrast, temperature and stratification increases are smaller in the Southern compared to the Northern Hemisphere. Additionally, a southward shift and increase in strength of the Southern Ocean westerlies act against increasing temperature and freshwater fluxes to destratify the water-column. The wind-driven, poleward shift in the Southern Ocean subpolar-subtropical boundary results in a poleward shift and increase in the frontal diatom bloom. This boundary shift, localized increases in iron supply, and the direct impact of warming temperatures on phytoplankton growth result in diatom increases in the Southern Hemisphere. An increase in diatoms and decrease in small phytoplankton partly compensate such that while total production and the efficiency of organic matter export to the deep ocean increase, total Southern Hemisphere biomass does not change substantially. The impact of ecological shifts on the global carbon cycle is complex and varies across ecological biomes, with Northern and Southern Hemisphere effects on the biological production and export partially compensating. The net result of climate change is a small Northern Hemisphere-driven decrease in total primary production and efficiency of organic matter export to the deep ocean.
    Description: I. Marinov was supported by National Science Foundation (NSF) Grant ATM06-28582 while at WHOI and by NASA Grant NNX13AC92G while at Penn. I. Lima and S. Doney were supported by the Center for Microbial Oceanography, Research, and Education (CMORE), an NSF Science and Technology Center (EF-0424599).
    Description: 2014-06-20
    Keywords: Phytoplankton ; Climate change ; Ocean models
    Repository Name: Woods Hole Open Access Server
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  • 21
    Publication Date: 2017-04-04
    Description: On 20 May 2012, at 02:03:52 GMT, an earthquake with Mw 6.1 (RCMT, http://www.bo.ingv.it/RCMT) occurred in northern Italy striking a densely populated area. The mainshock was followed a few hours later by two severe aftershocks having the same local magnitude (Ml 5.1, 1 and 2 in Figure 1a), and by hundreds of smaller aftershocks. Nine days later, on 29 May, at 07:00:03 GMT, a second event with moment magnitude Mw 6.0 (RCMT, http://www.bo.ingv.it/RCMT) occurred to the west, on an adjacent fault segment. This event was also followed by hundreds of aftershocks, three of them having local magnitude 5.3, 5.2 and 5.1 (3, 4 and 5, respectively, in Figure 1a) (locations from Istituto Nazionale di Geofisica e Vulcanologia, hereinafter INGV, http://iside.rm.ingv.it/; Malagnini et al., 2012; Scognamiglio et al., 2012). Despite the moderate number of casualties if compared to other major events in the Italian history, the economic loss was extremely high, resulting in about EUR 5 billion (AON Benfield, 2012, http://www.aon.com/), as the majority of Italian industrial activities and infrastructures concentrate in this area, the eastern Po plain, which is the largest sedimentary basin in Italy. The mainshocks are associated to two thrust faults with an approximate E-W trend dipping to the South (Figure 1b). The majority of the faults in this region are located in the upper crust, at depths lower than 10 km. The two main shocks are among the strongest earthquakes generated by thrust faults ever recorded in Italy in the instrumental era. The Emilia sequence has been extensively recorded by several strong-motion networks, operating in the Italian territory and neighbouring countries. Some of the networks acquire continuous data streams at their national data centres, which are nodes of EIDA (European Integrated Data Archive, hhtp://eida.rm.ingv.it), a federation of several archives, so that the waveforms can be obtained immediately after the occurrence of an event. Other networks, such as the Italian accelerometric network (RAN), managed by the Italian Department of the Civil Protection (hereinafter DPC), distribute the acceleration waveforms through their web site (http://protezionecivile.gov.it). The data set explored in this study is relative to the six events of the sequence having Ml 〉 5 (Table 1) and consists in 365 accelerograms recorded within a distance of 200 km from the epicentres, that were provided by the permanent and temporary seismic networks of INGV, the Swiss Seismological Service (SED, http://www.seismo.ethz.ch/index) and the DPC.
    Description: Published
    Description: 629-644
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: open
    Keywords: Strong motion ; May-June 2012 Emilia Romagna earthquake sequence ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
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  • 22
    Publication Date: 2022-05-25
    Description: © The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 3 (2013): 2802, doi:10.1038/srep02802.
    Description: It is usually assumed that metabolic constraints restrict deep-sea corals to cold-water habitats, with ‘deep-sea’ and ‘cold-water’ corals often used as synonymous. Here we report on the first measurements of biological characters of deep-sea corals from the central Red Sea, where they occur at temperatures exceeding 20°C in highly oligotrophic and oxygen-limited waters. Low respiration rates, low calcification rates, and minimized tissue cover indicate that a reduced metabolism is one of the key adaptations to prevailing environmental conditions. We investigated four sites and encountered six species of which at least two appear to be undescribed. One species is previously reported from the Red Sea but occurs in deep cold waters outside the Red Sea raising interesting questions about presumed environmental constraints for other deep-sea corals. Our findings suggest that the present understanding of deep-sea coral persistence and resilience needs to be revisited.
    Keywords: Ecosystem ecology ; Biodiversity ; Genetics ; Metabolism
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  • 23
    Publication Date: 2017-04-03
    Description: The seismic sequence that occurred in the Abruzzo Apennines near L’Aquila (Italy) in April 2009 caused extensive damage and a large number of casual- ties (more than 300). The earthquake struck an area in the Italian Apennines chain where several faults, belonging to adjacent seismotectonic domains, create a complex tectonic regime resulting from the interaction among regional stress buildup, local stress changes caused by individual earthquakes, and viscous-elastic stress relaxation. Understanding such complex interaction in the Apennines can lead to a large step for- ward in the seismic risk mitigation in Italy. The Abruzzo earthquake has been very well recorded by interferometric synthetic aperture radar (InSAR) data, much better than the first Italian earthquake ever recorded by satellites, namely, the 1997 Umbria–Marche earthquake. ENVISAT (ENVIronmental SATellite) data for the Abruzzo earthquake are, in fact, very clear and allow an accurate reconstruction of the faulting mechanism. We present here an accurate inversion of vertical deformation data obtained by ENVISAT images, aimed to give a detailed reconstruction of the fault geometry and slip distribu- tion. The resulting fault models are then used to compute, by a suitable theoretical model based on the elastic dislocation theory, the stress changes induced on the neigh- boring faults. The correlation of the subsequent mainshocks and aftershocks of the Abruzzo sequence with the volumes undergoing increasing Coulomb stress clearly evidence the triggering effect of coseismic stress changes on further seismicity. More- over, this analysis put in evidence which seismotectonic domains have been more heav- ily charged by stress released by the Abruzzo mainshocks. The most important faults significantly charged by the Abruzzo sequence belong to the Sulmona and Avezzano tectonic domains. Taking into account the average regional stress buildup in the area, the positive Coulomb stress changes caused by this earthquake can be seen as antici- pating the next earthquakes in the neighboring domains of 15–20 yr.
    Description: Published
    Description: 2340-2354
    Description: JCR Journal
    Description: restricted
    Keywords: Aquila Earthquakes of April 2009 ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
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  • 24
    Publication Date: 2017-04-04
    Description: Rapid evaluation of strong ground-shaking maps after moderate-to-large earthquakes is crucial to recognizing those areas where the largest damage and losses are expected. These maps play a fundamental role for emergency management. This is particularly important for areas having high seismic risk potential and covered by dense seismic networks. In near-real-time applications, ground-shaking maps are produced by integrating recorded data and estimates obtained by using ground-motion predictive equations, which assume point-source models. However, particularly for large earthquakes, improvements in the predictions of the peak ground motion can be obtained when fault extension and orientation are available. In fact, detailed source information allows one to use a more robust source-to-site distance metric compared with hypocentral distance. In this paper, a technique for estimating both fault extent (in terms of its surface projection) and dominant rupture direction is presented. This technique can be used in near-real-time ground-motion map calculation codes with the aim of improving ground-motion estimates with respect to a point-source model. The model parameters are estimated by maximizing a probability density function based on the residuals between observed and predicted peak-ground-motion quantities, the latter obtained by using predictive equations. The model space to be investigated is defined through a Bayesian approach, and it is explored by a grid-searching technique. The effectiveness of the proposed technique is demonstrated by offline numerical tests using data from three earthquakes occurring in different seismotectonic environments. The selected earthquakes are the 17 August 1999 Mw 7.5 Kocaeli (Turkey) earthquake, the 6 April 2009 Mw 6.3 L’Aquila (Italy) earthquake, and the 17 January 1994 Mw 6.7 Northridge (California) earthquake. The obtained results show that the proposed technique allows for fast and first order estimates of the fault extent and dominant rupture direction, which could be used to improve ground-shaking map calculations.
    Description: Published
    Description: 661-679
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: restricted
    Keywords: Source directivity ; ShakeMap ; L'Aquila earthquake ; Northridge earthquake ; Kocaeli earthquake ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
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  • 25
    Publication Date: 2017-04-03
    Description: The 2009 Mw 6.3 L’Aquila earthquake produced an impressive number of rotational effects on vertically organized objects such as chimneys, pillars, capitals, and gravestones. We present a dataset of such effects that consists of 105 observations at 37 different sites and represents a compendium of earthquake-induced instances of rotational effects that is unprecedented in recent times. We find that the absolute majority of the reported effects were observed in the epicentral zone and that most of the observations are located where the Mercalli–Cancani–Sieberg intensity is between 7 and 8–9. The evident asymmetry in the distribution of the rotational effects resembles the southeastward directivity of the macroseismic effects and highlights a significant convergence between rotations and damage. Finally, we perform some qualitative analyses to recognize and evaluate which geological and seismological parameters can be significant contributors to local rotations. We find that surface geology and amplification of the seismic motion at each reported location strongly influence the occurrence and the nature of the earthquake-induced rotational effects. Conversely, the contribution of the pattern of slip distribution on the fault plane plays only a secondary role in enhancing the rotational motion at each site.
    Description: Published
    Description: 1109-1120
    Description: JCR Journal
    Description: restricted
    Keywords: L’Aquila earthquake ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
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  • 26
    Publication Date: 2017-04-04
    Description: In widely used -2 source models the characteristics of high frequency radiation are described as being flat for frequencies between the source corner frequency and an upper limiting frequency fmax. Deviations from this behavior are described in a parameter which is understood as a general measure of the changes the signal undergoes on its way from the source to the receiver. In this study, we calculated  in Southeastern Sicily by using microearthquakes belonging to three different seismic sequences occurring in the area in 1990, 1999-2001, and 2002. The selected events form four different clusters whose seismic sources are located within a 2 km radius. Although the source-to-station paths are approximately the same inside a given cluster, the values of  change considerably at the same recording site from one event to another, also in the case of events having the same magnitude. We parameterized  in terms of event (E), and path (P and Diff) contributions. The term P represents the contribution on total  of both the whole source-to- station path and the near-surface geology, while Diff models the possible spatial variation in the parameter measured with respect to a reference source-station direction. Results show that the source contribution is not negligible and that there is a positive correlation with source size exists. Moreover, the hypothesis of a laterally homogeneous crustal structure within the area in question is not appropriate and significant variation in attenuating properties of the medium may occur in a very small distance range (also in the order of a few tens of meters). Our analysis suggests that the origin of the above mentioned variability is located near the recording site. Synthetic spectra are also computed in order to verify the actual significance of the parameterization employed and its capacity to separate the source and the path contribution to . We describe our spectra as a product of a Brune-type source spectrum and an exponential shaping term accounting for propagation effects. The seismic moments range between 3.8 ×1011 and 5.2 ×1013 N·m, the source radii range between 176 and 669 m, while the stress drop varies from 0.01 to 0.67 MPa.
    Description: Published
    Description: 1796-1809
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: open
    Keywords: High-frequency spectral decay in P-wave acceleration ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
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  • 27
    Publication Date: 2017-04-04
    Description: The recent Mw 6.3 destructive L’Aquila earthquake has further stimulated the improvement of the Italian operational earthquake forecasting capability at different time intervals. Here, we describe a medium-term (10-year) forecast model for Mw ≥5:5 earthquakes in Italy that aims at opening new possibilities for risk mitigation purposes. While a longer forecast yielded by the national seismic-hazard map is the primary component in establishing the building code, a medium-term earthquake forecast model may be useful to prioritize additional risk mitigation strategies such as the retrofitting of vulnerable structures. In particular, we have developed an earthquake occurrence model for a 10-year forecast that consists of a weighted average of time-independent and different types of available time-dependent models, based on seismotectonic zonations and regular grids. The inclusion of time-dependent models marks a difference with the earthquake occurrence model of the national seismic-hazard map, and it is motivated by the fact that, at the 10-year scale, the contribution of time-dependency in the earthquake occurrence process may play a major role. The models are assembled through a simple averaging scheme whereby each model is weighted through the results of a retrospective testing phase similar to the ones carried out in the framework of the Collaboratory for the Study of Earthquake Predictability. In this way, the most hazardous Italian areas in the next ten years will arise from a combination of distinct models that place more emphasis on different aspects of the earthquake occurrence process, such as earthquake clustering, historical seismic rate, and the presence of delayed faults capable of large events. Finally, we report new challenges and possible developments for future updating of the model.
    Description: Published
    Description: 1195-1213
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: restricted
    Keywords: Earthquake occurrence ; time-dependent and independent earthquake occurrence models ; csep testing ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
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  • 28
    Publication Date: 2022-05-25
    Description: © The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 2 (2012): 553, doi:10.1038/srep00553.
    Description: Sea surface temperature imagery, satellite altimetry, and a surface drifter track reveal an unusual tilt in the Gulf Stream path that brought the Gulf Stream to 39.9°N near the Middle Atlantic Bight shelfbreak—200 km north of its mean position—in October 2011, while a large meander brought Gulf Stream water within 12 km of the shelfbreak in December 2011. Near-bottom temperature measurements from lobster traps on the outer continental shelf south of New England show distinct warming events (temperature increases exceeding 6°C) in November and December 2011. Moored profiler measurements over the continental slope show high salinities and temperatures, suggesting that the warm water on the continental shelf originated in the Gulf Stream. The combination of unusual water properties over the shelf and slope in late fall and the subsequent mild winter may affect seasonal stratification and habitat selection for marine life over the continental shelf in 2012.
    Description: Profiler data were made available by the Ocean Observatory Initiative (OOI) during the construction phase of the project. The OOI is funded by the National Science Foundation and managed by the Consortium for Ocean Leadership. Drifter data were provided by Tim Shaw and David Calhoun at Cape Fear Community College.GGGwas supported by NSFGrant OCE-1129125. RET was supported by the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding provided by the Cooperative Institute for the North Atlantic Region. MA was supported by the Penzance Endowed Fund in Support of Assistant Scientists.
    Keywords: Ecology ; Climate change ; Atmospheric science ; Oceanography
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  • 29
    Publication Date: 2017-04-04
    Description: In this paper, we adopt three ground-motion simulation techniques (EXSIM, Motazedian and Atkinson, 2005, DSM, Pacor et al., 2005 and HIC, Gallovič and Brokešová, 2007), with the aim of investigating the different performances in near-fault strong-motion modeling and prediction from past and future events. The test case is the 1980, M 6.9, Irpinia earthquake, the strongest event recorded in Italy. First, we simulate the recorded strong-motion data and validate the model parameters by computing spectral acceleration and peak amplitudes residual distributions. The validated model is then used to investigate the influence of site effects and to compute synthetic ground motions around the fault. Afterward, we simulate the expected ground motions from scenario events on the Irpinia fault, varying the hypocenters, the rupture velocities and the slip distributions. We compare the median ground motions and related standard deviations from all scenario events with empirical ground motion prediction equations (GMPEs). The synthetic median values are included in the median ± one standard deviation of the considered GMPEs. Synthetic peak ground accelerations show median values smaller and with a faster decay with distance than the empirical ones. The synthetics total standard deviation is of the same order or smaller than the empirical one and it shows considerable differences from one simulation technique to another. We decomposed the total standard deviation into its between-scenario and within-scenario components. The larger contribution to the total sigma comes from the latter while the former is found to be smaller and in good agreement with empirical inter-event variability.
    Description: In press
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: restricted
    Keywords: Irpinia 1980 earthquake ; ground-motion simulation ; ground-motion variability ; scenario events ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
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  • 30
    Publication Date: 2017-04-04
    Description: The MW 8.8 mega-thrust earthquake and tsunami that occurred on February 27, 2010, offshore Maule region, Chile, was not unexpected. A clearly identified seismic gap existed in an area where tectonic loading has been accumulating since the great 1835 earthquake experienced and described by Darwin during the voyage of the Beagle. Here we jointly invert tsunami and geodetic data (InSAR, GPS, land-level changes), to derive a robust model for the co-seismic slip distribution and induced co-seismic stress changes, and compare them to past earthquakes and the pre-seismic locking distribution. We aim to assess if the Maule earthquake has filled the Darwin gap, decreasing the probability of a future shock . We find that the main slip patch is located to the north of the gap, overlapping the rupture zone of the MW 8.0 1928 earthquake, and that a secondary concentration of slip occurred to the south; the Darwin gap was only partially filled and a zone of high pre-seismic locking remains unbroken. This observation is not consistent with the assumption that distributions of seismic rupture might be correlated with pre-seismic locking, potentially allowing the anticipation of slip distributions in seismic gaps. Moreover, increased stress on this unbroken patch might have increased the probability of another major to great earthquake there in the near future.
    Description: Published
    Description: 173-177
    Description: 3.1. Fisica dei terremoti
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: restricted
    Keywords: Source process ; Chile ; Tsunami ; Joint Inversion ; Seismic Gap ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 31
    Publication Date: 2017-04-04
    Description: The analysis of the seismic attenuation is a prominent and problematic component of hazard assessment. Over the last decade it has become increasingly clear that the intrinsic uncertainty of the decay process must be expressed in probabilistic terms. This implies estimating the probability distribution of the intensity at a site Is as the combination of the distribution of the decay DI and of the distribution of the intensity I0 found for the area surrounding that site. We focus here on the estimation of the distribution of DI. Previous studies presented in the literature show that the intensity decay in Italian territory varies greatly from one region to another, and depends on many factors, some of them not easily measurable. Assuming that the decay shows a similar behavior in function of the epicenter-site distance when the same geophysical conditions and building vulnerability characterize different macroseismic fields, we have classified some macroseismic fields drawn from the Italian felt report database by applying a clustering algorithm. Earthquakes in the same class constitute the input of a two-step procedure for the Bayesian estimation of the probability distribution of I at any distance from the epicenter, conditioned on I0, where DI is considered an integer, random variable, following a binomial distribution. The scenario generated by a future earthquake is forecast either by the predictive distribution in each distance bin, or by a binomial distribution whose parameter is a continuous function of the distance. The estimated distributions have been applied to forecast the scenario actually produced by the Colfiorito earthquake on 1997/09/26; for both options the expected and observed intensities have been compared on the basis of some validation criteria. The same procedure has been repeated using the probability distribution of DI estimated on the basis of each class of macroseismic fields identified by the clustering algorithm.
    Description: Published
    Description: 2876-2892
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: open
    Keywords: Macroseismic fields ; Probability Distribution of the Intensity at Site ; Attenuation trends ; Colfiorito 1997 earthquake ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 32
    Publication Date: 2017-04-04
    Description: This study investigates the engineering applicability of two conceptually different finite-fault simulation techniques. We focus our attention on two important aspects: first to quantify the capability of the methods to reproduce the observed ground-motion parameters (peaks and integral quantities); second to quantify the dependence of the strong-motion parameters on the variability in the large-scale kinematic definition of the source (i.e., position of the nucleation point, value of the rupture velocity, and distribution of the final slip on the fault). We applied an approximated simulation technique, the deterministic-stochastic method and a broadband technique, the hybrid-integral-composite method, to model the 1984 Mw 5.7 Gubbio, central Italy, earthquake, at five accelerometric stations. We first optimize the position of the nucleation point and the value of the rupture velocity for three different final slip distributions on the fault by minimizing an error function in terms of acceleration response spectra in the frequency band from 1 to 9 Hz. We found that the best model is given by a rupture propagating at about 2:65 km=sec from a hypocenter located approximately at the center of the fault. In the second part of the article we calculate more than 2400 scenarios varying the kinematic source parameters. At the five sites we compute the residuals distributions for the various strongmotion parameters and show that their standard deviations depend on the source parameterization adopted by the two techniques. Furthermore, we show that Arias Intensity (AI) and significant duration are characterized by the largest and smallest standard deviation, respectively. Housner Intensity is better modeled and less affected by uncertainties in the source kinematic parameters than AI. The fact that the uncertainties in the kinematic model affects the variability of different ground-motion parameters in different ways has to be taken into account when performing hazard assessment and earthquake engineering studies for future events.
    Description: Published
    Description: 647-663
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: reserved
    Keywords: ground-motion simulation ; Gubbio 1984 ; ground-motion variability ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 33
    Publication Date: 2017-04-04
    Description: The Campi Flegrei caldera (southern Italy) is one of the most hazardous areas in the World as several hundred thousand people live there and where important socio-economic activities have developed. The caldera includes the western-most part of the city of Naples and extends into the Gulf of Pozzuoli (eastern Tyrrhenian basin; Fig. 1). The main feature of the present volcanic activity of the caldera is the episodic slow and high-amplitude soil movement (bradyseism) accompanied by intense and shallow seismic activity that only occurs during the uplift phase.
    Description: Published
    Description: 916-927
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 1.8. Osservazioni di geofisica ambientale
    Description: JCR Journal
    Description: restricted
    Keywords: Campi Flegrei ; volcanic activity ; seafloor monitoring ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 34
    Publication Date: 2017-04-04
    Description: The Mw6.3 2009 L’Aquila earthquake produced an impressive number of rotational effects on vertically organized objects such as chimneys, pillars, capitals and gravestones. We present the dataset of such effects, that consists of 105 observations at 37 different sites and represents a compendium of earthquake-induced istances of rotational effects that is unprecedented in recent times. We find that the absolute majority of the reported effects was observed in the epicentral zone and that most of the observations are located where the MCS intensity is between 7 and 8-9. The evident asymmetry in the distribution of the rotational effects resembles the southeastward directivity of the macroseismic effects and highlights a significant convergence between rotations and damage. Finally, we perform some qualitative analyses to recognize and evaluate which *Manuscript Click here to download Manuscript: revised_text.doc 2 geological and seismological parameters can be significant contributors to local rotations. We find that surface geology and amplification of the seismic motion at each reported location strongly influence the occurrence and the nature of the earthquake-induced rotational effects. Conversely, the contribution of the pattern of slip distribution on the fault plane plays only a secondary role in enhancing the rotational motion at each site.
    Description: In press
    Description: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale
    Description: JCR Journal
    Description: open
    Keywords: l'aquila earthquake ; rotationale effects ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 35
    Publication Date: 2017-04-04
    Description: This study investigates the engineering applicability of two conceptually different finite-fault simulation techniques. We focus our attention on two important aspects: first to quantify the capability of the methods to reproduce the observed ground-motion parameters (peaks and integral quantities); second to quantify the dependence of the strong-motion parameters on the variability in the large-scale kinematic definition of the source (i.e. position of nucleation point, value of the rupture velocity and distribution of the final slip on the fault). We applied an approximated simulation technique, the Deterministic-Stochastic Method DSM, and a broadband technique, the Hybrid-Integral-Composite method HIC, to model the 1984 Mw 5.7 Gubbio, central Italy, earthquake, at 5 accelerometric stations. We first optimize the position of nucleation point and the value of rupture velocity for three different final slip distributions on the fault by minimizing an error function in terms of acceleration response spectra in the frequency band from 1 to 9 Hz. We found that the best model is given by a rupture propagating at about 2.65 km/s from a hypocenter located approximately at the center of the fault. In the second part of the paper we calculate more than 2400 scenarios varying the kinematic source parameters. At the five sites we compute the residuals distributions for the various strong-motion parameters and show that their standard deviations depend on the source-parameterization adopted by the two techniques. Furthermore, we show that, Arias Intensity and significant duration are characterized by the largest and smallest standard deviation, respectively. Housner Intensity results better modeled and less affected by uncertainties in the source kinematic parameters than Arias Intensity. The fact that the uncertainties in the kinematic model affects the variability of different ground-motion parameters in different ways has to be taken into account when performing hazard assessment and earthquake engineering studies for future events.
    Description: In press
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: open
    Keywords: ground-motion simulation ; Gubbio 1984 ; ground-motion variability ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 36
    Publication Date: 2019-03-05
    Description: New duration-based local (ML) and moment (Mw) magnitude scales are obtained for the Campi Flegrei area through analysis of a dataset of local volcanotectonic earthquakes. First, the S-wave quality factor for the investigated area was experimentally calculated, and then the distance-correction curve, log A0(r), to be used in the Richter formula ML = log Amax − log A0(r), was numerically estimated by measuring the attenuation properties and, hence, propagating a synthetic S-wave packet in the earth medium. The local magnitude scale was normalized to fit the Richter formula that was valid for Southern California at a distance of 10 km. ML was estimated by synthesizing Wood–Anderson seismograms and measuring the maximum amplitude. For the same dataset, the moment magnitude was obtained from S-wave distance-corrected and site-corrected displacement spectra. Comparisons between local and moment magnitudes determined, along with the old duration magnitude (MD) routinely used at the Istituto Nazionale di Geofisica e Vulcanologia– Osservatorio Vesuviano, are presented and discussed. Moreover, the relationships between ML and Mw calculated for two reference sites are also derived.
    Description: Published
    Description: 1964-1974
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: open
    Keywords: magnitude ; Campi Flegrei ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 37
    Publication Date: 2017-04-04
    Description: The spatial distribution of 414 earthquakes (1.0 ≤ ML ≤ 4.6), recorded from 1994 to 2002 in Southeastern Sicily (Italy), has been analyzed; it generally coincides with mapped Plio-Quaternary faults, including the NNW-SSE offshore fault system which is the most important tectonic structure of the area. For the best located events, we computed 70 focal mechanisms by combining P-wave polarities with S-wave polarizations. A predominance of strike-slip and normal faults was observed. Focal mechanisms were then inverted for stress tensor parameters using the algorithm of Gephart and Forsyth. The results highlighted a region governed mainly by a compressional stress regime. Moreover, anisotropy analysis of shear-waves showed a polarization of fast S-waves prevalently aligned in the NNW-SSE to NW-SE direction over the whole area. A finer analysis of stress tensor evidenced three regions characterized by slightly differing orientation of the greatest principal stress axis, 1. The eastern sector displays a nearly horizontal 1 trending NW-SE; the central sector is affected by a low dip NNW-SSE 1; whereas in the western sector a 1 NNW-SSE oriented, with a higher dip angle, was detected. Finally, the comparison of the spatial distribution of seismicity occurring during 1994-2002, with locations of previous instrumental earthquakes and larger (M ≥ 5.0) historical events showed that the seismic patterns are persistent.
    Description: Published
    Description: 1359–1374
    Description: JCR Journal
    Description: reserved
    Keywords: Stress direction ; focal mechanisms ; Shear-Wave Anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 38
    Publication Date: 2017-04-04
    Description: In November 1999 and in January 2000, two microearthquake swarms occurred in Southeastern Sicily (Italy). They were analytically located in the depth range 17-25 km, some kilometers northward from the buried front of a regional foredeep, below the active thrust zone of the Sicily mountain chain. Their hypocentral distribution showed two distinct clusters, and comparison of the waveforms revealed clearly that the two swarms formed two distinct families of multiplet events. This led us: i) to carry out a precise relocation relative to two chosen master events of the families, and ii) to better define the geometrical structure of the two clusters. The cross-spectral method was applied to obtain precise readings of the wave onsets. SH-wave onsets were used instead of P-waves, as they showed clearer onsets and a good signal-to-noise ratio. Residuals of the relative locations showed small values, no more than several meters on average. The vertical extent of the two relocated clusters was 500 m and 250 m, respectively, while the horizontal extent was 250 m. Hypocenters of the first cluster clearly delineate a NNW trending plane with almost vertical dip, matching one nodal plane of the focal mechanism obtained as a composite solution of all events of the cluster. Given the considerable gap angles, because of unfavorable network geometry with respect to the events, the stability of our results was tested carrying out a Montecarlo experiment. Varying the onset times randomly in the range of 5 ms, a dispersion of the locations less than 10 m in longitude, and less than 50 m both in latitude and depth was found. Similar results were obtained when comparing relocations carried out with different master events. Thus, the overall geometrical characteristics of the clusters were not affected seriously by random errors. Considering the geo-structural framework of the region, together with the location and time evolution of the two clusters, fluids of plutonic origin are suggested as the trigger mechanism.
    Description: Published
    Description: 1479–1497
    Description: JCR Journal
    Description: reserved
    Keywords: earthquake swarms ; cross-correlation ; relative location ; master-event technique ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 39
    Publication Date: 2017-04-04
    Description: A long sequence of moderate-magnitude earthquakes (5 M 6) struck central Italy in September and October 1997. At the end of the sequence a year later, the seismogenic area extends for about 60 km along the Apennines. The analysis of historical seismicity suggests that this seismic sequence filled a 700-year gap in this portion of the chain. Other historical sequences in the same area are characterized by prolonged seismic release on adjacent fault segments, probably due to the involvement of shallow and complex structures inherited by the compressive tectonics. The distribution of seismicity and the fault-plane solutions show that the extension in this region is accomplished by normal faults dipping at relatively low angles ( 40 ) to the southwest. The focal mechanisms of the largest shocks reveal normal faulting with extension perpendicular to the Apenninic chain (northeast–southwest), consistently with the Quaternary tectonics of the internal sector of the northern Apennine belt and with previous earthquakes in adjacent regions. Three mainshocks occurred on distinct 5- to 10-km-long fault segments, adjacent and slightly offset between each other. High-quality aftershock locations show that seismicity is confined within the sedimentary Mesozoic cover in the upper 8 km of the crust and that most of the aftershocks are shallower than the largest shocks, which nucleated at 6-km depth. Faults evidenced by aftershock locations have a planar geometry and show increased complexity toward the surface. Most of the aftershock focal mechanisms are dominated by normal faulting. Several strike-slip events occurred at shallow depths, reactivating portions of pre-existing thrust planes that segment the normal fault system. The spatiotemporal evolution of seismicity shows a peculiar migration of hypocenters along the strike of the main faults with multiple ruptures and the activation of fault segments before the occurrence of the main rupture episodes.
    Description: Published
    Description: 99-116
    Description: reserved
    Keywords: Seismic ; Sequence ; Central Italy ; Apennines ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 2909303 bytes
    Format: application/pdf
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