Continuous Deformation Monitoring Research Articles

Non-interferometric GB-SAR measurement: application to the Vallcebre landslide (eastern Pyrenees, Spain)

Abstract. In the last decade, ground-based interferometry has proven to be a powerful technique for continuous deformation monitoring of landslides, glaciers, volcanoes, or manmade structures, among others. However, several limitations need to be addressed in order to improve the performances of the technique, especially for long-term monitoring. These limitations include the reduction of measurable points with an increase in the period of observation, the ambiguous nature of the phase measurements, and the influence of the atmospheric phase component. In this paper, a new procedure to process the amplitude component of ground-based synthetic aperture radar (GB-SAR) data acquired in discontinuous mode is compared and validated. The use of geometric features of the amplitude images combined with a matching technique will allow the estimation of the displacements over specific targets. Experimental results obtained during 19 months, in eight different campaigns carried out in the active landslide of Vallcebre (eastern Pyrenees, Spain), were analysed. During the observed period, from February 2010 to September 2011, displacements up to 80 cm were measured. The comparison with other surveying technique shows that the precision of the method is below 1 cm.

Precision Evaluation of Georobot Automatic Continuous Deformation Monitoring

Georobot is widely used to precision engineering measurement, especially in automatic continuous deformation monitoring, e.g. dam and landslide deformation monitoring, in virtue of the unique ATR and tracking technology. However it is hard to evaluate the actual tracking measurement precision because of the complex circumstance in specific application. The paper designs reasonable experiments solution, including test of tracking measurement of the stationary target point for the positioning precision and test of tracking measurement of the regular shape for the measuring deformation precision. The experiment result shows the positioning precision and measuring deformation precision both can reach the sub-millimeter level if centering error is eliminated, otherwise maybe in about 1.5mm level. It validates the reliability and efficiency of Georobot in automatic continuous deformation monitoring.

Continuous monitoring of wooden works of art using fiber Bragg grating sensors

In recent years the control and monitoring of works of art has gained more and more importance. In particular, works partially or totally realized with wood, such as polychrome sculptures, painted panels or Crucifixes, are highly sensitive and delicate and thus need a particular attention. The wooden support is, in fact, an essential element for the stability of pictorial layers: the color lies on a preparation, which in turn, is anchored to the wood. Wrong conservation methods, i.e. in an environmental climate that is not controlled, or intrinsic mechanical stresses, can warp such structures, and the effects can be irreversible and destructive to the painted layer. The use of fiber Bragg grating (FBG) sensors for the quasi-distributed, in situ measurement and continuous monitoring of deformations in painted wood panel is proposed. In order to demonstrate the applicability of FBG sensors to painted wood panels, a wooden support, made using the same 15th–16th century techniques, was prepared in the Opificio laboratories. A number of Bragg grating sensors were affixed in several critical points, on the back and front sides and on the strengthening cross-beams, in order to detect deformations in the panel dependent on the variations in the environmental relative humidity (RH). Measurements during the removal of the cross-beams are also reported. The results of measurements have shown the applicability of FBG sensors for the continuous in situ monitoring of valuable wooden objects and works of art.

Vulcanology: Interaction between Kilauea and Mauna Loa.

Last year witnessed an unexpected communication between this pair of volcanoes. After almost a decade of very slow rates of deformation, Mauna Loa in Hawaii, the largest volcano on Earth, began inflating in May 2002; at the same time, a high-volume effusive episode began at its neighbour Kilauea. We have found a correlation between these events at a very short timescale, detected by continuous deformation monitoring. This remarkable observation suggests that there is a crustal-level interaction between the magma systems of Mauna Loa and Kilauea, reviving a century-old controversy over the relationship between these two volcanoes on the basis of differences in their lava chemistry and in their patterns of eruptive behaviour1,2,3,4,5.

B35 地殻変動観測から推定された 1998-1999 年の岩手山のマグマ貫入プロセス

B35 地殻変動観測から推定された 1998-1999 年の岩手山のマグマ貫入プロセス

Geophysics. Silent slip on the Cascadia subduction interface.

Sensor arrays based on the Global Positioning System permit increasingly precise, continuous monitoring of deformation in Earth9s crust. In his Perspective, Thatcher highlights the report by Dragert et al ., who have analyzed data from one such array and have detected a silent (aseismic) slip event in a subduction zone. Such events would normally be expected to be associated with recent earthquake activity. Much remains to be learned about earthquake stress buildup, but thanks to GPS and other technologies, our understanding of earthquakes is rapidly expanding.

Continuous Deformation Monitoring With GPS

The U.S. Army Corps of Engineers makes extensive use of modern instrumentation for measuring the behavior of large structures. One of these programs is high‐precision geodetic surveying. This is accomplished through the use of classical techniques and provides a reliable measure of displacement as a function of time. Unfortunately, it is a labor‐intensive endeavor, and thus surveys are made infrequently. With the deployment of the NAVSTAR GPS, a possibility for continuous, automatic monitoring of structures has materialized. Preliminary designs suggest that desk‐top computers can be used with relatively simple data links to monitor a network of GPS receivers. The data can subsequently be processed and a deformation analysis can be performed to compute deformation vectors at a precision of about 0.5 cm. This paper presents a preliminary design for a complete system to be demonstrated at a Corps project in early 1989.