XCORR: A cross-over technique to adjust track data

Hsu, Shu-Kun

doi:10.1016/0098-3004(94)00070-b

Cited by 19 publications

(13 citation statements)

References 6 publications

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“…Crossover analysis results in a mean crossover error of −5.7 nT with a standard deviation of the crossover misfits of 159.5 nT. Crossover data corrections [ Hsu , 1995] performed using weights that decrease with age (i.e., more recent data are considered more accurate) result in a significant reduction of the misfit with final values of the mean crossover error of −0.95 nT and a standard deviation of the misfits of 25.3 nT. The compilation of magnetic data was smoothed and gridded at 250 m using the Generic Mapping Tools' blockmedian (1 km blocks) function followed by the greenspline function using a minimum curvature spline with a tension of 0.2 [ Wessel and Smith , 1991].…”

Section: Datamentioning

confidence: 99%

Multiple expressions of plume‐ridge interaction in the Galápagos: Volcanic lineaments and ridge jumps

Mittelstaedt¹,

Soule²,

Harpp³

et al. 2012

Geochem Geophys Geosyst

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[1] Anomalous volcanism and tectonics between near-ridge mantle plumes and mid-ocean ridges provide important insights into the mechanics of plume-lithosphere interaction. We present new observations and analysis of multibeam, side scan sonar, sub-bottom chirp, and total magnetic field data collected during the R/V Melville FLAMINGO cruise (MV1007; May-June, 2010) to the Northern Galápagos Volcanic Province (NGVP), the region between the Galápagos Archipelago and the Galápagos Spreading Center (GSC) on the Nazca Plate, and to the region east of the Galápagos Transform Fault (GTF) on the Cocos Plate. The NGVP exhibits pervasive off-axis volcanism related to the nearby Galápagos hot spot, which has dominated the tectonic evolution of the region. Observations indicate that $94% of the excess volcanism in our Copyright 2012 by the American Geophysical Union 1 of 31 survey area occurs on the Nazca Plate in three volcanic lineaments. Identified faults in the NGVP are consistent with normal ridge spreading except for those within a $60 km wide swath of transform-oblique faults centered on the GTF. These transform-oblique faults are sub-parallel to the elongation direction of larger lineament volcanoes, suggesting that lineament formation is influenced by the lithospheric stress field.We evaluate current models for lineament formation using existing and new observations as well as numerical models of mantle upwelling and melting. The data support a model where the lithospheric stress field controls the location of volcanism along the lineaments while several processes likely supply melt to these eruptions. Synthetic magnetic models and an inversion for crustal magnetization are used to determine the tectonic history of the study area. Results are consistent with creation of the GTF by two southward ridge jumps, part of a series of jumps that have maintained a plume-ridge separation distance of 145 km to 215 km since $5 Ma.

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Section: Datamentioning

confidence: 99%

Multiple expressions of plume‐ridge interaction in the Galápagos: Volcanic lineaments and ridge jumps

Mittelstaedt¹,

Soule²,

Harpp³

et al. 2012

Geochem Geophys Geosyst

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“…This clearly indicates that marine magnetic data are heterogeneously distributed, and thus affecting the assessment of the global quality of this data set. Crossover analyses [ Wessel and Watts , 1988; Hsu , 1995; Thakur et al , 1999] are here used. The anomaly crossover difference (COD) between two tracks should reflect the error budget.…”

Section: Marine Magnetic Datamentioning

confidence: 99%

A new global marine magnetic anomaly data set

2009

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[1] The Geophysical Data System (GEODAS) stores more than 20 million magnetic measurements acquired over oceans and seas since the 1950s. Usually, the original total field (TF) and magnetic anomaly values are both stored. The anomaly results from the subtraction of the core and external magnetic field estimates from TF values. The most recent International Geomagnetic Reference Field models available at the time of the surveys were used to estimate the core field component (these models were revised later). External fields were estimated from magnetic observatory data. However, most of the measurements were not corrected for the external fields. Here we use comprehensive models to properly remove the core and external magnetic fields from all original TF measurements stored in the GEODAS. Besides, a track-by-track analysis of each data is necessary mainly to correct or to remove many shifted values as well as to reduce the noise in some track lines. Two additional processes are applied to obtain a data set coherent over the world. It includes an adjustment of long-wavelength magnetic anomalies using the National Geophysical Data Center (NGDC) -720 model, plus a line leveling method which mainly reduced some inconsistencies between different surveys. The root mean square of the crossover differences was reduced from 179.6 to 35.9 nT. Comparisons of magnetic anomaly maps before and after our treatment also highlight an improvement in the quality and the coherence of the data set. This study will serve to build a new World Digital Magnetic Anomaly Map.

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Section: Kinematic Gps Datamentioning

confidence: 99%

“…Assuming this accuracy, the analysis of the residuals between height determinations can be discussed in terms of a normal distribution, leading to an estimation of the mean value and the standard deviation of the distribution. The algorithm used in this study for the COE was proposed by Hsu (1995). Although special care was taken in attempting to attain continuous data acquisition with a regular spacing (constant operator speed), a few stops were made by operators during the survey.…”

Section: Crossover Error Analysis Of the Kinematic Survey (Days 158 Amentioning

confidence: 99%

Digital photogrammetry and kinematic GPS applied to the monitoring of Vulcano Island, Aeolian Arc, Italy

Baldi

Bonvalot

Briole

et al. 2000

Geophysical Journal International

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Digital photogrammetry and kinematic global positioning system (GPS) techniques are investigated and compared over a volcanic area as operational approaches to map the topography and monitor surface displacements. The use of terrestrial and airborne GPS to support the photogrammetric survey allowed for operational and processing time reduction without loss of accuracy. A digital elevation model (DEM) is obtained from the processing of the high‐resolution digital imagery survey, which provides detailed information over a large area. The internal accuracy of the derived DEM has been verified by the comparison of two sets of data obtained from imagery acquired in different epochs; the observed root‐mean‐square error of residuals ranges from a few centimetres to 15 cm depending on the morphological features. Kinematic and pseudo‐kinematic GPS surveys are performed to derive accurate 3‐D coordinates at monumented benchmarks and accurate elevation profiles along footpaths. The average repeatability of the GPS measurements on benchmarks is 1 cm for measurement durations of 2–3 min. The standard deviation of interpolated vertical coordinates obtained at the crossings of kinematic GPS profiles is 4.3 cm. The high quality of these GPS coordinates justifies their use also for the validation of the photogrammetric DEM. A comparison of 6000 common points provides a standard deviation of residuals of 18 cm. The results show that the deformation pattern of a volcanic area can be rapidly and accurately monitored even in the absence of geodetic benchmarks. The integration of aerial photogrammetry with GPS kinematic surveys may be considered as an optimal approach for deriving high‐resolution mapping products to be used in support of studies of volcanic dynamics.

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XCORR: A cross-over technique to adjust track data

Cited by 19 publications

References 6 publications

Multiple expressions of plume‐ridge interaction in the Galápagos: Volcanic lineaments and ridge jumps

Multiple expressions of plume‐ridge interaction in the Galápagos: Volcanic lineaments and ridge jumps

A new global marine magnetic anomaly data set

Digital photogrammetry and kinematic GPS applied to the monitoring of Vulcano Island, Aeolian Arc, Italy

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