Monitoring Earthquakes with gravity meters

in Geodesy and Geodynamics (2011), 2(3), 71-75

Earthquake Monitoring with Gravity Meters: Case studies from the November 2006 and January 2007 Kuril Islands Earthquakes

Scientific Conference (2010, August 15)

Simultaneous observation of gravity tide in Juneau, Southeast Alaska with gPhone#32 and L&R G578 gravimeters

Speeches/Talks (2010)

Final report on absolute gravimeter intercomparison (EURAMET Project no. 1093)

in Metrologia (2010), 47(1A), 07008

An interlaboratory comparison (Euramet Project 1039) of three absolute gravimeters was carried out between the national metrology institutes of Luxembourg, Belgium and Switzerland (University of ... [more ▼]

An interlaboratory comparison (Euramet Project 1039) of three absolute gravimeters was carried out between the national metrology institutes of Luxembourg, Belgium and Switzerland (University of Luxembourg/ECGS, Royal Observatory of Belgium and Federal Office for Metrology METAS). The comparison was hosted in the Underground Laboratory for Geodynamics in Walferdange. The obtained results confirm a perfect agreement between the instruments used with respective expanded uncertainties ( k = 2) of 4.25 µGal. Finally, a link to the Euramet project 1030 shows that the three gravimeters are coherent with the 19 other gravimeters. Main text. To reach the main text of this paper, click on Final Report [http://www.bipm.org/utils/common/pdf/final_reports/M/G-S1/EURAMET.M.G-S1.pdf] . Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/ [http://kcdb.bipm.org/] . The final report has been peer-reviewed and approved for publication by EURAMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA). [less ▲]

On the influence of the rotation of a corner cube reflector in absolute gravimetry

in Metrologia (2010), 47(5), 567

Test masses of absolute gravimeters contain prism or hollow retroreflectors. A rotation of such a retroreflector during free-fall can cause a bias in the measured g -value. In particular, prism ... [more ▼]

Test masses of absolute gravimeters contain prism or hollow retroreflectors. A rotation of such a retroreflector during free-fall can cause a bias in the measured g -value. In particular, prism retroreflectors produce phase shifts, which cannot be eliminated. Such an error is small if the rotation occurs about the optical centre of the retroreflector; however, under certain initial conditions the error can reach the microgal level. The contribution from these rotation-induced accelerations is calculated. [less ▲]

欧洲绝对重力仪比对观测 (ECGS’07)

in 地球物理学进展 (Progress in Geophysics) (2009), 24(6), 2054-2057

Relative Gravity Measurement Campaign during the 7th International Comparison of Absolute Gravimeters (2005)

in Metrologia (2009), 46(3), 214

Since the 1st International Comparison of Absolute Gravimeters (ICAG) and accompanying Relative Gravity Campaign (RGC) held at the BIPM in 1981, repeated ICAG-RGCs have been organized every four years. A ... [more ▼]

Since the 1st International Comparison of Absolute Gravimeters (ICAG) and accompanying Relative Gravity Campaign (RGC) held at the BIPM in 1981, repeated ICAG-RGCs have been organized every four years. A total of 19 absolute gravimeters (AG) and 15 relative gravimeters (RG) participated in the 7th ICAG-RGC, which took place in 2005. Co-located absolute and relative gravity measurements as well as precision levelling measurements were carried out. The final version of the absolute g values of the 7th ICAG has been officially released recently. This paper is the final report of the 7th RGC and replaces the preliminary results published earlier. It covers the organization of the RGC and the data processing, analyses RG behaviour, computes g , δ g and O AG (offset of AG) and discusses their uncertainties. In preparation for the BIPM key comparison ICAG-2009, a standard data-processing procedure has been developed and installed in the BIPM ICAG-RGC software package, GraviSoft. This was used for the final data processing. [less ▲]

Absolute gravity measurements at the Conrad Observatorium in Austria in June 2008

Report (2008)

Geodetic measurements of postglacial adjustments in Greenland

in Journal of Geophysical Research (2008)

We analyze data from seven continuous Global Positioning System (GPS) receivers and one tide gauge, all located along the edge of the Greenland ice sheet, to determine vertical uplift rates. We compare ... [more ▼]

We analyze data from seven continuous Global Positioning System (GPS) receivers and one tide gauge, all located along the edge of the Greenland ice sheet, to determine vertical uplift rates. We compare our results with predictions based on the ICE-5G deglaciation model of Peltier (2004). Results from the GPS receiver at Kellyville (-1.2 ± 1.1 mm/a) and from the tide gauge at Nuuk (-2.2 ± 1.3 mm/a), indicate that ICE-5G overestimates the subsidence rates at those locations by 2.1 and 1.1 mm/a, respectively. Kellyville and Nuuk are located along the southwestern margin of the Greenland ice sheet, and the observed negative uplift rates are consistent with independent evidence that the ice margin along the southwestern edge readvanced during the last ~8 ka to its current position. The ICE-5G glaciation-deglaciation history includes a readvance between the latitudes of 62°N and 72°N. The GPS measurements suggest the ICE-5G readvance may be too large or mistimed. Our GPS results at Qaqortoq, located at the southern tip of Greenland, suggest a secular subsidence rate of 􏰀0.3 ± 1.1 mm/a, while ICE-5G predicts an uplift rate of 1.0 mm/a. ICE-5G assumes no ice sheet readvance in south Greenland, including no readvance of the Qassimiut lobe. The difference of 1.3 ± 1.1 mm/a can tentatively be explained as due to a ~33 km readvance of the Qassimiut lobe during the last ~3 ka. For the other GPS sites, the observed/predicted uplift rates are 3.6 ± 1.1/-0.1 mm/a at Thule, 0.0 ± 1.1/2.0 mm/a at Scoresbysund, and -0.4 ± 1.1/-1.7 mm/a at Kulusuk. For Thule, Kulusuk, and Scoresbysund the differences between the observed and predicted rates are on the order of 1.3 – 3.7 mm/a, though with opposite signs, and indicate that ICE-5G does not exactly reproduce the correct rebound signal at those locations. [less ▲]

Investigations of characteristics of gravimetric sites intended for high-accuracy measurements

in Peshekhonov, Vladimir (Ed.) Proceedings of the International Symposium on Terrestrial Gravimetry: static and mobile measurements (2008)