Abstract Dynamic earthquake rupture causes mass redistribution around the fault, and emitted propagating seismic waves are accompanied by bulk density perturbations. Both processes cause transient gravity changes prior to arrival of P-waves. Such pre-P signals have been detected in previous studies several large earthquakes. However, detections were limited vertical component signal owing high ...

We use ambient-noise-based seismic monitoring to detect an anomalous velocity decrease (?0.01%) widely distributed in Honshu that arose about 1 year after the 2011 Mw 9.0 Tohoku-Oki earthquake. The anomaly is located along central quaternary volcanic axis, and it suggests changes are related processes. After correction for possible external environmental forcing-related changes, remains, which ...

This work demonstrates the usage of two new quartz instruments, which are a tiltmeter and an extensometer that we developed lately to measure with high accuracy deformations of structures, volcanoes, tunnels, and ground surface. The stability of an underground quarry, near Paris in France was the subject of the study. The deformation of the quarry under different cases of loading during the pro...

[1] During the past decades, the research into fluid-controlled geodynamic processes in the upper crust of the Earth is put foreward regarding the stress accumulation, deformation, and seismicity. In a large-scale injection experiment at the deep borehole site KTB (Kontinentale Tiefbohrung der Bundesrepublik Deutschland) in Germany, more than 84.000 m fresh water was injected in 4000 m depth ov...

We analyzed seismicity linked to the 2014 phreatic eruption of Mount Ontake, Japan, on 27 September 2014. We first relocated shallow volcano tectonic (VT) earthquakes and long-period (LP) events from August to September 2014. By applying a matched-filter technique to continuous waveforms using these relocated earthquakes, we detected numerous additional micro-earthquakes beneath the craters. Th...

There is considerable interest in using remote elastostatic deformations to identify the evolving geometry of underground fractures that are forced to propagate by the injection of a high pressure viscous fluid. These so-called hydraulic fractures are used to increase the permeability in oil and gas reservoirs as well as to pre-fracture ore-bodies in preparation for a mining process known as bl...

Tilt vibrations inevitably have negative effects on some precise engineering even after applying horizontal and vertical vibration isolations. It is difficult to adopt a traditional passive isolation (PVI) scheme realize tilt isolation. In this paper, we present develop active (AVI) device using pendulum (VP) tiltmeter piezoelectric transducer (PZT). The potential resolution of the VP dependent...

Abstract. Since 2004 a research project has been developed to monitor subsurface deformation of Italian volcanoes using borehole strainmeters and long-baseline tiltmeters. Six Sacks-Evertson dilatometers were installed around Campi Flegrei caldera Vesuvius during 2004–2005 (Scarpa et al., 2007), in 2008 these instruments supplemented by two arrays 28–280 m long water-tube tiltmeters underground...