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L Salo - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Energy Analysis as Generated by Impact and Fragmentation of Single‐Block Experimental Rockfalls
    Journal of Geophysical Research, 2018
    Co-Authors: L Salo, Jordi Corominas, Nieves Lantada, Gerard Matas, Albert Prades, Roger Ruiz-carulla
    Abstract:

    The analysis of Seismic signals obtained from near-source triaxial accelerometer recordings of two sets of single-block rockfall experiments is presented. The tests were carried out under controlled conditions in two quarries in northeastern Spain; in the first test (Foj limestone quarry, Barcelona), 30 blocks were released with masses ranging between 475 and 11,480 kg. The second test (Ponderosa andesite quarry, Tarragona) consisted of the release of 44 blocks with masses from 466 to 13,581 kg. An accelerometer and three high-speed video cameras were deployed, so that the trajectories, velocities, and block fragmentation could be tracked precisely. These data were used to explore the relationship between Seismic Energy and rockfall kinetics (the latter obtained from video analysis). We determined absolute and relative values of Seismic Energy and used them to estimate rockfall volumes. Finally, the Seismic signature of block fragmentation was assessed in both the frequency and time domains. The ratios of Seismic Energy after impact to kinetic Energy before impact ranged between 10-7 and 10-4. These variables were weakly correlated. The use of Seismic Energy relative to impacting kinetic Energy was preferred for the estimation of volumes. Block fragmentation impacts were dominated by higher acceleration spectrum centroid frequencies than those of nonfragmentation impacts: 56.62 ± 2.88 and 48.46 ± 4.39 Hz at Foj and 52.84 ± 12.73 and 38.14 ± 4.73 Hz at Ponderosa.

  • Seismic Energy analysis as generated by impact and fragmentation of single block experimental rockfalls
    Journal of Geophysical Research, 2018
    Co-Authors: L Salo, Jordi Corominas, Nieves Lantada, Gerard Matas, Albert Prades, Roger Ruizcarulla
    Abstract:

    The analysis of Seismic signals obtained from near-source triaxial accelerometer recordings of two sets of single-block rockfall experiments is presented. The tests were carried out under controlled conditions in two quarries in northeastern Spain; in the first test (Foj limestone quarry, Barcelona), 30 blocks were released with masses ranging between 475 and 11,480 kg. The second test (Ponderosa andesite quarry, Tarragona) consisted of the release of 44 blocks with masses from 466 to 13,581 kg. An accelerometer and three high-speed video cameras were deployed, so that the trajectories, velocities, and block fragmentation could be tracked precisely. These data were used to explore the relationship between Seismic Energy and rockfall kinetics (the latter obtained from video analysis). We determined absolute and relative values of Seismic Energy and used them to estimate rockfall volumes. Finally, the Seismic signature of block fragmentation was assessed in both the frequency and time domains. The ratios of Seismic Energy after impact to kinetic Energy before impact ranged between 10-7 and 10-4. These variables were weakly correlated. The use of Seismic Energy relative to impacting kinetic Energy was preferred for the estimation of volumes. Block fragmentation impacts were dominated by higher acceleration spectrum centroid frequencies than those of nonfragmentation impacts: 56.62 ± 2.88 and 48.46 ± 4.39 Hz at Foj and 52.84 ± 12.73 and 38.14 ± 4.73 Hz at Ponderosa.

Kazushige Obara - One of the best experts on this subject based on the ideXlab platform.

  • spatiotemporal distribution of Seismic Energy radiation from low frequency tremor in western shikoku japan
    Journal of Geophysical Research, 2009
    Co-Authors: Takuto Maeda, Kazushige Obara
    Abstract:

    [1] The spatiotemporal patterns of the radiated Seismic Energy from low-frequency tremor associated with slow slip events in western Shikoku, Japan, have been estimated. A spatially decaying mean square amplitude and differential traveltime measurement from envelope correlations observed at Hi-net stations were used to locate tremors and to estimate their Seismic energies. Tremor amplitude was corrected for the site amplification factors estimated using the coda normalization method. The location of the tremor is estimated as the position where both the decay of the observed Energy and the differential travel times are well explained. The temporal pattern of the total Energy released agrees very well with the observed tilt records. Although the spatial patterns of the Energy radiation vary strongly among the six slow slip events (SSEs) in western Shikoku, the region where they overlap always radiates relatively high levels of Energy. The estimated band-limited Energy rate of the tremor for a 2 to 10 Hz bandwidth was typically between 105 and 106 J/min, though there is temporal variation of the radiation Energy. The released total Energy associated with the SSEs whose magnitude is 5.9–6.1 is on the order of 108 J within the duration of SSEs of 8–13 days. This is quite small Energy radiation compared to the moment release of accompanying SSE. The scaled Energy, which is the ratio of the Seismic moment and the Seismic Energy, for the slow slip and a very low frequency earthquake was estimated to be 5 orders of magnitude smaller than that of a regular earthquake.

  • Spatiotemporal distribution of Seismic Energy radiation from low‐frequency tremor in western Shikoku, Japan
    Journal of Geophysical Research, 2009
    Co-Authors: Takuto Maeda, Kazushige Obara
    Abstract:

    [1] The spatiotemporal patterns of the radiated Seismic Energy from low-frequency tremor associated with slow slip events in western Shikoku, Japan, have been estimated. A spatially decaying mean square amplitude and differential traveltime measurement from envelope correlations observed at Hi-net stations were used to locate tremors and to estimate their Seismic energies. Tremor amplitude was corrected for the site amplification factors estimated using the coda normalization method. The location of the tremor is estimated as the position where both the decay of the observed Energy and the differential travel times are well explained. The temporal pattern of the total Energy released agrees very well with the observed tilt records. Although the spatial patterns of the Energy radiation vary strongly among the six slow slip events (SSEs) in western Shikoku, the region where they overlap always radiates relatively high levels of Energy. The estimated band-limited Energy rate of the tremor for a 2 to 10 Hz bandwidth was typically between 105 and 106 J/min, though there is temporal variation of the radiation Energy. The released total Energy associated with the SSEs whose magnitude is 5.9–6.1 is on the order of 108 J within the duration of SSEs of 8–13 days. This is quite small Energy radiation compared to the moment release of accompanying SSE. The scaled Energy, which is the ratio of the Seismic moment and the Seismic Energy, for the slow slip and a very low frequency earthquake was estimated to be 5 orders of magnitude smaller than that of a regular earthquake.

Roger Ruizcarulla - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Energy analysis as generated by impact and fragmentation of single block experimental rockfalls
    Journal of Geophysical Research, 2018
    Co-Authors: L Salo, Jordi Corominas, Nieves Lantada, Gerard Matas, Albert Prades, Roger Ruizcarulla
    Abstract:

    The analysis of Seismic signals obtained from near-source triaxial accelerometer recordings of two sets of single-block rockfall experiments is presented. The tests were carried out under controlled conditions in two quarries in northeastern Spain; in the first test (Foj limestone quarry, Barcelona), 30 blocks were released with masses ranging between 475 and 11,480 kg. The second test (Ponderosa andesite quarry, Tarragona) consisted of the release of 44 blocks with masses from 466 to 13,581 kg. An accelerometer and three high-speed video cameras were deployed, so that the trajectories, velocities, and block fragmentation could be tracked precisely. These data were used to explore the relationship between Seismic Energy and rockfall kinetics (the latter obtained from video analysis). We determined absolute and relative values of Seismic Energy and used them to estimate rockfall volumes. Finally, the Seismic signature of block fragmentation was assessed in both the frequency and time domains. The ratios of Seismic Energy after impact to kinetic Energy before impact ranged between 10-7 and 10-4. These variables were weakly correlated. The use of Seismic Energy relative to impacting kinetic Energy was preferred for the estimation of volumes. Block fragmentation impacts were dominated by higher acceleration spectrum centroid frequencies than those of nonfragmentation impacts: 56.62 ± 2.88 and 48.46 ± 4.39 Hz at Foj and 52.84 ± 12.73 and 38.14 ± 4.73 Hz at Ponderosa.

Suguru Yabe - One of the best experts on this subject based on the ideXlab platform.

  • spatial distribution of Seismic Energy rate of tectonic tremors in subduction zones
    Journal of Geophysical Research, 2014
    Co-Authors: Suguru Yabe
    Abstract:

    The sizes of deep tectonic tremors have never been accurately evaluated as a physical quantity. Here we estimate tremor size as the band-limited Seismic Energy rate at 2–8 Hz, with accurate evaluation of the path attenuation and site amplification of Seismic waves in four subduction zones: Nankai, Cascadia, Jalisco, and South Chile. The size-frequency statistics of Seismic Energy rate, which are characterized by the median measure for each subregion, are spatially variable. The spatial variations are categorized into three types, with each type corresponding to a different tremor migration behavior. In type A regions where tremor zone is wider, Seismic Energy rates are highly variable in the dip direction, and tremor activities are usually initiated in the less energetic tremor zone. Some of them further penetrate into the energetic tremor zone and subsequently migrate for long distances in the strike direction. Type B regions are characterized by relatively narrow tremor zones, minor variations in Energy rates in the dip direction, and long-distance migration in the strike direction. Type C regions are characterized by isolated clusters of tremor activities without migration and by independent failure of each small tremor cluster. Given that the spatial distributions of tremor Energy rates reflect heterogeneities in the strength of the plate interface, such distributions, which would be controlled by the width of tremor zone, may determine the regional style of slow-earthquake behavior. Some energetic tremor regions act as switches that trigger large slow slip events, especially in type A regions.

Takuto Maeda - One of the best experts on this subject based on the ideXlab platform.

  • spatiotemporal distribution of Seismic Energy radiation from low frequency tremor in western shikoku japan
    Journal of Geophysical Research, 2009
    Co-Authors: Takuto Maeda, Kazushige Obara
    Abstract:

    [1] The spatiotemporal patterns of the radiated Seismic Energy from low-frequency tremor associated with slow slip events in western Shikoku, Japan, have been estimated. A spatially decaying mean square amplitude and differential traveltime measurement from envelope correlations observed at Hi-net stations were used to locate tremors and to estimate their Seismic energies. Tremor amplitude was corrected for the site amplification factors estimated using the coda normalization method. The location of the tremor is estimated as the position where both the decay of the observed Energy and the differential travel times are well explained. The temporal pattern of the total Energy released agrees very well with the observed tilt records. Although the spatial patterns of the Energy radiation vary strongly among the six slow slip events (SSEs) in western Shikoku, the region where they overlap always radiates relatively high levels of Energy. The estimated band-limited Energy rate of the tremor for a 2 to 10 Hz bandwidth was typically between 105 and 106 J/min, though there is temporal variation of the radiation Energy. The released total Energy associated with the SSEs whose magnitude is 5.9–6.1 is on the order of 108 J within the duration of SSEs of 8–13 days. This is quite small Energy radiation compared to the moment release of accompanying SSE. The scaled Energy, which is the ratio of the Seismic moment and the Seismic Energy, for the slow slip and a very low frequency earthquake was estimated to be 5 orders of magnitude smaller than that of a regular earthquake.

  • Spatiotemporal distribution of Seismic Energy radiation from low‐frequency tremor in western Shikoku, Japan
    Journal of Geophysical Research, 2009
    Co-Authors: Takuto Maeda, Kazushige Obara
    Abstract:

    [1] The spatiotemporal patterns of the radiated Seismic Energy from low-frequency tremor associated with slow slip events in western Shikoku, Japan, have been estimated. A spatially decaying mean square amplitude and differential traveltime measurement from envelope correlations observed at Hi-net stations were used to locate tremors and to estimate their Seismic energies. Tremor amplitude was corrected for the site amplification factors estimated using the coda normalization method. The location of the tremor is estimated as the position where both the decay of the observed Energy and the differential travel times are well explained. The temporal pattern of the total Energy released agrees very well with the observed tilt records. Although the spatial patterns of the Energy radiation vary strongly among the six slow slip events (SSEs) in western Shikoku, the region where they overlap always radiates relatively high levels of Energy. The estimated band-limited Energy rate of the tremor for a 2 to 10 Hz bandwidth was typically between 105 and 106 J/min, though there is temporal variation of the radiation Energy. The released total Energy associated with the SSEs whose magnitude is 5.9–6.1 is on the order of 108 J within the duration of SSEs of 8–13 days. This is quite small Energy radiation compared to the moment release of accompanying SSE. The scaled Energy, which is the ratio of the Seismic moment and the Seismic Energy, for the slow slip and a very low frequency earthquake was estimated to be 5 orders of magnitude smaller than that of a regular earthquake.