Next Article in Journal
Near Field Communication: Technology and Market Trends
Previous Article in Journal / Special Issue
Crustal Strain Observation Using a Two-Color Interferometer with Accurate Correction of Refractive Index of Air
Article Menu

Export Article

Open AccessArticle
Technologies 2014, 2(3), 129-142; doi:10.3390/technologies2030129

A 100-m Fabry–Pérot Cavity with Automatic Alignment Controls for Long-Term Observations of Earth’s Strain

1
Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
2
Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
3
National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
4
Institute for Cosmic Ray Research, The University of Tokyo, 238 Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205, Japan
*
Author to whom correspondence should be addressed.
Received: 29 April 2014 / Revised: 27 June 2014 / Accepted: 15 July 2014 / Published: 6 August 2014
(This article belongs to the Special Issue Precision Measurements and Metrology Using Lasers)
View Full-Text   |   Download PDF [1087 KB, uploaded 6 August 2014]   |  

Abstract

We have developed and built a highly accurate laser strainmeter for geophysical observations. It features the precise length measurement of a 100-m optical cavity with reference to a stable quantum standard. Unlike conventional laser strainmeters based on simple Michelson interferometers that require uninterrupted fringe counting to track the evolution of ground deformations, this instrument is able to determine the absolute length of a cavity at any given time. The instrument offers advantage in covering a variety of geophysical events, ranging from instantaneous earthquakes to crustal deformations associated with tectonic strain changes that persist over time. An automatic alignment control and an autonomous relocking system have been developed to realize stable performance and maximize observation times. It was installed in a deep underground site at the Kamioka mine in Japan, and an effective resolution of 2 × (10−8 − 10−7) m was achieved. The regular tidal deformations and co-seismic strain changes were in good agreement with those from a theoretical model and a co-located conventional laser strainmeter. Only the new instrument was able to record large strain steps caused by a nearby large earthquake because of its capability of absolute length determination. View Full-Text
Keywords: absolute distance determination; earthquake monitoring; laser strainmeter; optical cavity alignment absolute distance determination; earthquake monitoring; laser strainmeter; optical cavity alignment
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Takamori, A.; Araya, A.; Morii, W.; Telada, S.; Uchiyama, T.; Ohashi, M. A 100-m Fabry–Pérot Cavity with Automatic Alignment Controls for Long-Term Observations of Earth’s Strain. Technologies 2014, 2, 129-142.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Technologies EISSN 2227-7080 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top