Comparison of point and array-computed rotations for the TAIGER explosions of 4 March 2008

Kendall, Lauren; Langston, Charles A.; Lee, W. H. K.; Lin, Chin‐Jen; Liu, C. C.

doi:10.1007/s10950-012-9297-4

Cited by 7 publications

(5 citation statements)

References 18 publications

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“…Alternatively, the seismogeodetic method [Bodin et al, 1997;Spudich et al, 1995;Spudich and Fletcher, 2008] may be used to derive rotational ground motion from translation recordings at the surface [e.g., Suryanto et al, 2006;Kendall et al, 2012;Pham et al, 2012]. This method requires, however, detailed knowledge of 3-D subsurface structure.…”

Section: Measuring Rotational Ground Motionsmentioning

confidence: 99%

“…While the vertical component of rotational ground motion can be approximated via finite differences from translational recordings at the surface, a similar approximation of the horizontal components would require borehole seismometers that are mostly unavailable. Alternatively, the seismogeodetic method [Bodin et al, 1997;Spudich et al, 1995;Spudich and Fletcher, 2008] may be used to derive rotational ground motion from translation recordings at the surface [e.g., Suryanto et al, 2006;Kendall et al, 2012;Pham et al, 2012]. This method requires, however, detailed knowledge of 3-D subsurface structure.…”

Section: Measuring Rotational Ground Motionsmentioning

confidence: 99%

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Reducing nonuniqueness in finite source inversion using rotational ground motions

2014

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We assess the potential of rotational ground motion recordings to reduce nonuniqueness in kinematic source inversions, with emphasis on the required measurement accuracy of currently developed rotation sensors. Our analysis is based on synthetic Bayesian finite source inversions that avoid linearizations and provide a comprehensive quantification of uncertainties and trade-offs. Using the fault and receiver geometry of the Tottori 2000 earthquake as a test bed, we perform inversions for two scenarios: In scenario I, we use translational velocity recordings only. In scenario II, we randomly replace half of the velocity recordings by rotation recordings, thus keeping the total amount of data constant. To quantify the noise-dependent impact of rotation recordings, we perform a sequence of inversions with varying noise levels of rotations relative to translations. Our results indicate that the incorporation of rotational ground motion recordings can significantly reduce nonuniqueness in finite source inversions, provided that measurement uncertainties are similar to or below the uncertainties of translational velocity recordings. When this condition is met, rupture velocity and rise time benefit most from rotation data. The trade-offs between both parameters are then strongly reduced, and the information gain nearly doubles. This suggests that rotational ground motion recordings may improve secondary inferences that rely on accurate information about rise time and rupture velocity. These include frictional properties of the fault, radiation directivity, and ground motion in general.

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Section: Measuring Rotational Ground Motionsmentioning

confidence: 99%

Section: Measuring Rotational Ground Motionsmentioning

confidence: 99%

Reducing nonuniqueness in finite source inversion using rotational ground motions

2014

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“…We see that they are much more similar to each other than in Figure 14, especially ∆v z /∆y (green curves), i.e., the best ADR estimate (but still far from being accurate) can be expected for Ω x (axis in the N-S direction). (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) Hz) finite differences, ∆v x /∆y (blue), ∆v y /∆x (green), x-axis pointing to the North, y-axis pointing to the West. The large dots mark the stations in the array (see Figure 2).…”

Section: Velocity Records and Velocity Spatial Gradientsmentioning

confidence: 99%

“…As an overwhelming majority of seismic rotational data are records of motions very weak in amplitude, such experiments should be focused on that rather than on strong motion records. To verify Rotaphone data for weak events, we designed a comparative in-field experiment (inspired by the paper by Kendall et al [ 19 ]). The experiment consisted in comparing Rotaphone records with those from the Eentec R-1 rotational sensor and the array-derived-rotation (ADR) data.…”

Section: Introductionmentioning

confidence: 99%

Comparative Measurements of Local Seismic Rotations by Three Independent Methods

Brokešová

Málek

2020

Sensors

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A comparative active experiment that is aimed at collocated measurement of seismic rotation rates along three orthogonal axes by means of three different methods is described. The rotation rates in a short-period range of 6–20 Hz were obtained using three different methods: the 6C Rotaphone sensor system developed by the authors, the commercial R-1 rotational sensor by Eentec, and a small-aperture array of twelve standard velocigraphs in a rectangular arrangement. Those three methods are compared and discussed in detail. A medium-size quarry blast was used as a seismic source. At a distance of approximately 240 m, the rotation rates reached an amplitude of the order of magnitude of 10−4–10−5 rad/s. The array derived rotation rates displayed serious limitations, as clearly documented. The R-1 instruments have shown certain technical problems that partly limit their applicability. The measured rotation rates were compared to the relevant acceleration components according to rotation-to-translation relations. Out of all the three methods, the records best matching the acceleration components were made by Rotaphone. The experiment also revealed that rotation rates in the given short-period range noticeably changed over a distance as short as 2 m.

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“…Ring laser gyroscopes are capable of measuring torsional rates at a precision of 10 −10 rad/s [ Igel et al , ], but are unaffordable for the seismology community to deploy extensively [ Lee et al , ]. Medium‐priced rotational sensors, e.g., eentec R1 with a nominal precision of 10 −6 rad/s, however, have not proven reliable in faithfully recording broadband rotational motions [ Kendall et al , ; Wassermann et al , ]. Alternatively, coseismic rotations can be indirectly measured using a dense seismic array according to linear elasticity theory by presuming a spatially uniform rotational pattern over the extent of the array [e.g., Huang , ; Spudich et al , ].…”

Section: Introductionmentioning

confidence: 99%

Recovering coseismic point ground tilts from collocated high‐rate GPS and accelerometers

Geng

Melgar

Bock

et al. 2013

Geophysical Research Letters

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[1] Rotational along with translational and strain measurements are essential for a complete description of the motion of a deformable body in a seismic event. We propose a new seismogeodetic approach where collocated high-rate GPS and accelerometer measurements are combined to estimate permanent and dynamic coseismic ground tilts at a point, whereas at present, only dynamic tilts are measured with either a dense seismic array or an expensive ring laser gyroscope. We estimate point tilts for a five-story structure on a shake table subjected to 13 earthquake strong motion records of increasing intensity. For the most intense record from the 2002 M7.9 Denali earthquake, we observe a peak-to-peak dynamic tilt of 0.12 ı and a permanent tilt of 0.16 ı for the structure's roof. Point tilts derived from networks of collocated GPS and accelerometers can be used to estimate the rotational component of the seismic wavefield for improved earthquake source characterization. Citation: Geng, J., D.Melgar, Y. Bock, E. Pantoli, and J. Restrepo (2013), Recovering coseismic point ground tilts from collocated high-rate

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Comparison of point and array-computed rotations for the TAIGER explosions of 4 March 2008

Cited by 7 publications

References 18 publications

Reducing nonuniqueness in finite source inversion using rotational ground motions

Reducing nonuniqueness in finite source inversion using rotational ground motions

Comparative Measurements of Local Seismic Rotations by Three Independent Methods

Recovering coseismic point ground tilts from collocated high‐rate GPS and accelerometers

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