Why Do My Squiggles Look Funny? A Gallery of Compromised Seismic Signals

Ringler, Adam T.; Mason, D. P.; Laske, G.; Storm, Tyler; Templeton, Mary

doi:10.1785/0220210094

Cited by 6 publications

(3 citation statements)

References 39 publications

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“…Each estimate requires at least 90% data completeness within each 1-hour window. We zero-pad any data gaps within the 1-hour segments after linearly detrending each contiguous data segment to avoid broadband discontinuity-induced spectral artifacts 60 . For each subwindow we apply a Hann taper and calculate their average, removing the instrument response to obtain physical units as parameterized by authoritative EarthScope Data Management Center metadata, and returning acceleration PSD estimates in dB relative to 1 (ms −2 ) 2 /Hz.…”

Section: Methodsmentioning

confidence: 99%

Increasing ocean wave energy observed in Earth’s seismic wavefield since the late 20th century

Aster,

Ringler,

Anthony

et al. 2023

Nat Commun

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Ocean waves excite continuous globally observable seismic signals. We use data from 52 globally distributed seismographs to analyze the vertical component primary microseism wavefield at 14–20 s period between the late 1980s and August 2022. This signal is principally composed of Rayleigh waves generated by ocean wave seafloor tractions at less than several hundred meters depth, and is thus a proxy for near-coastal swell activity. Here we show that increasing seismic amplitudes at 3σ significance occur at 41 (79%) and negative trends occur at 3σ significance at eight (15%) sites. The greatest absolute increase occurs for the Antarctic Peninsula with respective acceleration amplitude and energy trends ( ± 3σ) of 0.037 ± 0.008 nm s−2y−1 (0.36 ± 0.08% y−1) and 4.16 ± 1.07 nm2 s−2y−1 (0.58 ± 0.15% y−1), where percentage trends are relative to historical medians. The inferred global mean near-coastal ocean wave energy increase rate is 0.27 ± 0.03% y−1 for all data and is 0.35 ± 0.04% y−1 since 1 January 2000. Strongly correlated seismic amplitude station histories occur to beyond 50∘ of separation and show regional-to-global associations with El Niño and La Niña events.

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Section: Methodsmentioning

confidence: 99%

Increasing ocean wave energy observed in Earth’s seismic wavefield since the late 20th century

Aster,

Ringler,

Anthony

et al. 2023

Nat Commun

Self Cite

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“…Data used in the inversion were screened by excluding any data that were excessively noisy, such that the signal from the landslide was not visible when displacement waveforms were filtered to the frequency band of interest (period range of 15–250 s), or that had data gaps or other signal issues (e.g., Ringler et al., 2021). We did not impose a zero‐amplitude requirement on the data prior to the start time of the signal (which is sometimes done to remove precursory noise related to the band‐limited nature of the inversion, see Section 5.2) to allow for a more direct comparison with the filtered runout model results, discussed in the following section.…”

Section: Methodsmentioning

confidence: 99%

Insights on Multistage Rock Avalanche Behavior From Runout Modeling Constrained by Seismic Inversions

et al. 2022

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Inversion of low‐frequency regional seismic records to solve for a time series of bulk forces exerted on the earth by a landslide (a force‐time function) is increasingly being used to infer volumes and dynamics of large, highly energetic landslides, such as rock avalanches and flowslides, and to provide calibration information on event dynamics and volumes for numerical landslide runout models. Much of the work to date using landslide runout modeling constrained by seismic data has focused on using single‐phase models with frictional or velocity‐weakening rheologies. Awareness of multistage landslide initiations is increasing, with discrete failures separated in time contributing to the final impact of an event. Our work utilizes a method for incorporating seismic data as a calibration constraint for landslide runout models, considering variable rheologies and different initiation conditions. This study presents a systematic examination of multiple rheologies and initiation conditions, and shows how these factors affect the force‐time function derived from the landslide runout model. Our work confirms that, while rheology and fragmenting or initially coherent initiations affect the force‐time function, multiple collapses separated by tens of seconds have the greatest impact on the shape and amplitude. We apply this method to the analysis of three real rock avalanches to better constrain plausible initiation conditions and rheology parameters using both seismic and field data. This study provides insights on how assumptions about the initiation dynamics of the source zone and the runout model definition can aid in the interpretation of seismic inversions for multistage rock avalanches.

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“…Each estimate requires at least 90% data completeness within the 1-hour window. We zero-pad any data gaps within the 1-hour segments after linearly detrending each contiguous data segment to avoid broadband discontinuity-induced spectral artifacts [73]. For each subwindow we apply a Hann taper and calculate their average, removing the instrument response to obtain physical units as parameterized by authoritative DMC metadata, and returning acceleration PSD estimates in dB relative to 1 (nm/s 2 ) 2 /Hz.…”

Section: Appendix B Spectral Estimationmentioning

confidence: 99%

Increasing near-coastal ocean wave energy observed in Earth’s seismic wavefield since the late 1980

Aster

Ringler

Anthony

et al. 2023

Preprint

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Earth’s seismic wavefield is continuously excited by forces on the seafloor arising from ocean gravity waves. The resulting microseism signal is detected worldwide by seismographic networks, even in the deep interiors of the continents, and its spatially and temporally variations reflect global ocean wave conditions. The primary microseism signal between 20 – 14 s period is principally composed of seismic Rayleigh waves that represent the spatiotemporal integrated seismic radiation excited across near coastal bathymetry. We analyze primary microseism vertical-component amplitudes, which are insensitive to Rayleigh wave propagation direction, through late 2022 using continuous seismic data recorded by globally distributed seismographs with operational intervals exceeding 20 years and beginning with the advent of modern continuous digital broadband recording in the late 1980s. Widespread increasing median amplitudes are apparent at the majority of global stations even prior to removing non-seismic instrumental and large earthquake signals and subtraction of the stationary component of the annual signal. Increasing primary microseism amplitudes and energies at 3σ significance occur for 41 of 52 stations. Significant decreasing trends for stations are geographically restricted to the northern and western Pacific region and to two sites in the southern United States. Amplitude and energy changes show broad proportionality, with the greatest absolute increases occurring at stations with historically high microseism levels. The most rapidly proportionately intensifying energy occurs at eastern North American and European sites that are principally sensitive to wave energy in the North Atlantic, and which show median average seismic energy increases over the past three decades of 0.7 – 0.8% per year relative to long-term median values. median values. The most rapidly intensifying primary microseism levels on an absolute basis are observed for the Antarctic Peninsula with an annualized vertical seismic acceleration, velocity, and energy trends (3σ uncertainties) of 0.037 ± 0.008 nm/s2/yr (0.36 ± 0.08 %/yr), 0.093 ± 0.02 nm/s/yr (0.35 ± 0.08 %/yr), and 4.16 ± 1.07 (nm/s)2 (0.58 ± 0.15 %/yr), respectively. Average inferred wave energy increase from seismic energy metrics across analyzed stations is 0.27±0.03 %/yr for the entire data period and 0.35±0.04 %/yr for the era beginning on January 1 2000.

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Why Do My Squiggles Look Funny? A Gallery of Compromised Seismic Signals

Cited by 6 publications

References 39 publications

Increasing ocean wave energy observed in Earth’s seismic wavefield since the late 20th century

Increasing ocean wave energy observed in Earth’s seismic wavefield since the late 20th century

Insights on Multistage Rock Avalanche Behavior From Runout Modeling Constrained by Seismic Inversions

Increasing near-coastal ocean wave energy observed in Earth’s seismic wavefield since the late 1980

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