ROMY: a multicomponent ring laser for geodesy and geophysics. Issue 1 (5th January 2021)

• Record Type: Journal Article
• Authors: Igel, Heiner; Schreiber, Karl Ulrich; Gebauer, André; Bernauer, Felix; Egdorf, Sven; Simonelli, Andrea; Lin, Chin-Jen; Wassermann, Joachim; Donner, Stefanie; Hadziioannou, Céline; Yuan, Shihao; Brotzer, Andreas; Kodet, Jan; Tanimoto, Toshiro; Hugentobler, Urs; Wells, Jon-Paul R
• Is Part Of: Geophysical journal international. Volume 225:Issue 1(2021)
• Page Start: 684
• Page End: 698
• Publication Date: 2021-01-05
• Subjects: Earth rotation variations -- Geodetic instrumentation -- Earthquake ground motions -- Rotational seismology -- Seismic instruments -- Seismic noise; Geophysics -- Periodicals; 550
• DOI: 10.1093/gji/ggaa614
• Languages: English
• ISSNs: 0956-540X

Abstract

SUMMARY: Single-component ring lasers have provided high-resolution observations of Earth's rotation rate as well as local earthquake- or otherwise-induced rotational ground motions. Here, we present the design, construction and operational aspects of ROMY, a four-component, tetrahedral-shaped ring laser installed at the Geophysical Observatory Fürstenfeldbruck near Munich, Germany. Four equilateral, triangular-shaped ring lasers with 12 m side length provide rotational motions that can be combined to construct the complete vector of Earth's rotation from a point measurement with very high resolution. Combined with a classic broad-band seismometer, we obtain the most accurate 6 degree-of-freedom ground motion measurement system to date, enabling local and teleseismic observations as well as the analysis of ocean-generated Love and Rayleigh waves. The specific design and construction details are discussed as are the resulting consequences for permanent observations. We present seismic observations of local, regional and global earthquakes as well as seasonal variations of ocean-generated rotation noise. The current resolution of polar motion is discussed and strategies how to further improve long-term stability of the multicomponent ring laser system are presented.