scholarly journals Remote Detection of the Electric Field Change Induced at the Seismic Wave Front from the Start of Fault Rupturing

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Yukio Fujinawa ◽  
Kozo Takahashi ◽  
Yoichi Noda ◽  
Hiroshi Iitaka ◽  
Shinobu Yazaki
Keyword(s):  
Electric Field ◽  
Seismic Waves ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Warning System ◽  
Wave Mode ◽  
P Wave ◽  
Remote Detection ◽  
Electrokinetic Effect ◽  
Earthquake Early Warning System

Seismic waves are generally observed through the measurement of undulating elastic ground motion. We report the remote detection of the Earth's electric field variations almost simultaneously with the start of fault rupturing at about 100 km from the fault region using a special electric measurement. The rare but repeated detection indicates that the phenomenon is real. The characteristic time of diffusion is almost instantaneous, that is, less than 1 second to travel 100 km, more than ten times faster than ordinary seismic P wave propagation. We suggest that the measured electric field changes are produced by the electrokinetic effect through increased pore water pressure of the seismic pulse. It is also suggested that the long range propagation is due to the surface wave mode confined near the interface of the different conductivity. The length scale of the finite strength of the electric field is 16 km, 160 km for electric conductivity of 0.01, 0.001, Sm−1, respectively. This phenomenon suggests a new seismic sensing method and a new earthquake early warning system providing more seconds of lead time.

scholarly journals Development of Earthquake Early Warning System Using ADXL335 Accelerometer

2018 ◽  
Author(s):  
Yoga Priyana ◽  
Folkes E. Laumal ◽  
Emir E. Husni
Keyword(s):  
Early Warning ◽  
Early Warning System ◽  
Seismic Waves ◽  
Human Life ◽  
Warning System ◽  
Earthquake Early Warning ◽  
P Wave ◽  
Earthquake Early Warning System ◽  
Wave Data ◽  
Seismic Sensors

Indonesia is an archipelago located at three earthquake belts. This condition cause an earthquake can occur anytime and threaten human life. A quick and accurate early warning system by using the seismic wave data processing is required so, the number of victims affected by the earthquake can be shortened. Here, ADXL335 accelerometers are used as seismic sensors with an Arduino minimum system. The results show that when the first earthquake’s vibration occurs, P wave data detected by the ADXL335 sensor is successfully buffered, calibrated, transmitted and displayed on the server. When there are errors on the transmission, server will request for retransmission. The alarm of the earthquake early warning system will be activated if there are at least three sensors from different locations successfully transmit P wave data with the same scale. This is needed to prevent fake seismic waves.

Slope Monitoring System at a Slope Behind an Important Cultural Asset

2011 ◽  
Vol 6 (1) ◽  
pp. 70-79 ◽  
Author(s):  
Kazunari Sako ◽  
◽  
Ryoichi Fukagawa ◽  
Tomoaki Satomi ◽  
◽  
...  
Keyword(s):  
Field Measurement ◽  
Slope Failure ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Numerical Models ◽  
Water Pressure ◽  
Measurement Data ◽  
Warning System ◽  
Set Up ◽  
Relationship Of

Rainfall-induced slope failure has been responsible for great death and destruction in Japan. This is thus a primary consideration in preserving Japan’s many cultural important temples, palaces, and similar structures, especially in the ancient capital of Kyoto, where many important cultural assets are located on hillsides and near mountains. Our objective is to construct a slope-disaster warning system using real-time field measurement data, in-situ and laboratory testing, and numerical models. We set up field monitoring on a slope behind an important cultural asset in July 2004 to measure pore-water pressure, temperature, and rainfall intensity [1]. We firstly introduce our slope-disaster warning concept and field measurement results for the slope behind the important cultural asset in Kyoto. And then we discuss the relationship of rainfall intensity, seepage behavior, and slope failure based on monitoring data and model test results using a soil box apparatus.

P-wave tomographic model from local bulletin data for improved seismic location in and around Israel

2020 ◽  
Author(s):  
Lewis Schardong ◽  
Yochai Ben-Horin ◽  
Alon Ziv ◽  
Hillel Wust-Bloch ◽  
Yael Radzyner
Keyword(s):  
Eastern Mediterranean ◽  
A Priori ◽  
Warning System ◽  
Velocity Model ◽  
P Wave ◽  
Seismic Velocities ◽  
Fast Marching ◽  
Earthquake Early Warning System ◽  
Starting Model ◽  
Correction Terms

<p>For the past 40 years, the Geophysical Institute of Israel has been in charge of the recording, monitoring and relocating of local earthquakes. Due to the variety of data analysts and data sources, as well as several network upgrades, the resulting bulletin data has to be completed and homogenised, and station metadata needs to be tracked down, and sometimes corrected. For those reasons, as well as because of the lack of consensus on an accurate model for seismic velocities in the area, published source locations are often poorly constrained. We present a homogenised Israeli bulletin, including natural and man-made explosion data. We extract sets of seismic sources with location accuracy greater than 5 km (GT5), as well as GT0 explosions.</p><p>We select a set of events with the highest network coverage, comprising (1) natural earthquakes, (2) man-made quarry or mine blasts, (3) GT5 earthquakes or explosions, and (4) GT0 explosions. We relocate them altogether using the <em>BayesLoc</em> package, a Bayesian, hierarchical, multi-event locator which produces, after source relocation, event-, station- and phase-specific correction terms. We put different a priori constraints on the different categories of seismic events, allowing poorly constrained origin parameters to improve thanks to the more accurate GT locations. <em>BayesLoc</em> also produces traveltime correction terms that can be used to correct systematic errors in the dataset, as well as error estimates.</p><p>Eventually, we invert this homogenised local traveltime dataset in order to invert for a <em>P</em>-wave crustal velocity model of Israel and its surroundings. To do so, we use the <em>Fast Marching Tomography</em> package, which allows the representation of a wide variety of input structures (starting model and geometry of layer boundaries) and can take many different types of input data. We show preliminary inversion tests and results that are in good agreement with past local studies.</p><p>This crustal model of Israel is ultimately to be used as a starting model in a larger tomographic study of the Eastern Mediterranean and Middle East region, where the <em>Regional Seismic Travel Time</em> approach is to be expanded, in order to improve the CTBT’s capabilities in monitoring the regional seismicity. Eventually, such a velocity model could also be used to relocate the whole earthquake catalogue more accurately, and improve the Earthquake Early Warning System currently in development in Israel.</p>

A new instrument in earthquake early warning system by detection and modeling of prompt gravity signals

2020 ◽  
Author(s):  
Kevin Juhel ◽  
Jean-Paul Montagner ◽  
Jean-Paul Ampuero ◽  
Matteo Barsuglia ◽  
Pascal Bernard ◽  
...  
Keyword(s):  
Early Warning ◽  
Seismic Noise ◽  
Seismic Waves ◽  
Matched Filter ◽  
Accurate Determination ◽  
Warning System ◽  
Tohoku Earthquake ◽  
Earthquake Early Warning ◽  
Earthquake Early Warning System ◽  
New Instrument

<p>The recent finding of prompt elastogravity signals (PEGS) before the arrival of P-waves, associated with the M9.1 2011 Tohoku earthquake (Montagner et al., Nat. Comm., 2016; Vallée et al., Science, 2017) and a few earthquakes of magnitude larger than 8.5  (Vallée and Juhel, JGR, 2019) opens the new field of speed-of-light seismology.  The systematic detection of PEGS on real-time might help saving a few seconds before the arrival of destructive seismic waves and to obtain an accurate determination of the magnitude of the earthquake at the end of rupture. So the potential application to earthquake early warning is obvious.</p><p>However, the use of classical broadband seismometers for detecting PEGS has severe limitations for detecting earthquakes of magnitude smaller than 8.5: first of all, the background seismic noise and second of all, the partial cancellation of the gravitational perturbation by the inertial induced acceleration recorded by seismometers (Heaton, Nature Comm., 2017). Two different approaches can be explored for detecting for earthquakes of magnitude smaller than 8.5. Either, by using a dense array of broadband seismometers  (more than 100 receivers) or by designing completely new instruments such as gravity strainmeters. These new detectors must be able to measure the difference in gravity acceleration between two masses, making this instrument isolated from the seismic noise. A sensitivity of 10<sup>-15 </sup>Hz<sup>-1/2</sup> at 0.1 Hz is required for detecting earthquakes of M>7 (Juhel et al., JGR, 2019) and the technology developed by the gravitational wave physicists can be used for reaching such a sensitivity. The simulation of the expected gravity strain signals based on analytical model of gravity perturbations associated with a network-based matched filter approach show that a network of 3 gravity strainmeters might make it possible to reach such a challenging goal. Gravity strainmeters could therefore open new ways to investigate the first seconds of the earthquake rupture, speed up the estimate of earthquake magnitude, enhance tsunami warning systems and  complement other EEWS in the future.</p><p> </p><p> </p>

scholarly journals Progressive failure of a constrained creeping landslide

2011 ◽  
Vol 467 (2133) ◽  
pp. 2444-2461 ◽  
Author(s):  
Alexander M. Puzrin ◽  
Andreas Schmid
Keyword(s):  
Slip Surface ◽  
Pore Water Pressure ◽  
Progressive Failure ◽  
Water Pressure ◽  
Field Tests ◽  
Warning System ◽  
Earth Pressure ◽  
Compression Zone ◽  
Slowing Down ◽  
In The Beginning

The ski resort town of St Moritz, Switzerland, is partially constructed on a large creeping landslide, which has been causing damage to buildings and infrastructure. At the town centre, the landslide is constrained by a rock outcrop, creating a compression zone in the sliding mass. After decades of gradual slowing down,s in the beginning of 1990s the landslide started to accelerate, in spite of the fact that the average yearly precipitation and the pore water pressure on the sliding surface remained fairly constant. The paper shows that a constrained creeping landslide experiences progressive failure caused by the propagation of a zone of intense shearing along the slip surface resulting in significant earth pressure increase and visco-plastic yielding of soil in the compression zone. This basic physical mechanism, relying on extensive laboratory and field tests and long-term displacement monitoring, explains the paradox of the St Moritz landslide acceleration. Although the model predicts that the landslide could eventually slow down, its displacements may become excessive for some buildings, requiring an early warning system and further stabilization of the historic Leaning Tower. In general, by predicting the onset of yielding, the model can provide an important timeframe for stabilization of constrained landslides.

scholarly journals The scaling of PGA with IV2p and its potential for Earthquake Early Warning in Thessaly (Central Greece)

2021 ◽  
Vol 58 ◽  
pp. 177
Author(s):  
Ioannis Spingos ◽  
Filippos Vallianatos ◽  
George Kaviris
Keyword(s):  
Early Warning ◽  
Scaling Laws ◽  
Warning System ◽  
Seismic Signal ◽  
Earthquake Early Warning ◽  
P Wave ◽  
Scaling Relations ◽  
Initial Portion ◽  
Earthquake Early Warning System ◽  
Single Station

The main goal of an Earthquake Early Warning System (EEWS) is to estimate the expected peak ground motion of the destructive S-waves using the first few seconds of P-waves, thus becoming an operational tool for real-time seismic risk management in a short timescale. EEWSs are based on the use of scaling relations between parameters measured on the initial portion of the seismic signal, after the arrival of the first wave. Herein, using the abundant seismicity that followed the 3 March 2021 Mw=6.3 earthquake in Thessaly we propose scaling relations for PGA, from data recorded by local permanent stations, as a function of the integral of the squared velocity (IV2p). The IV2p parameter was estimated directly from the first few seconds-long signal window (tw) after the P-wave arrival. Scaling laws are extrapolated for both individual and across sites (i.e., between a near-source reference instrument and a station located close to a target). The latter approach is newly investigated, as local site effects could have a significant impact on recorded data. Considering that further study on the behavior of IV2p is necessary, there are indications that this parameter could be used in future on-site single‐station earthquake early warning operations for areas affected by earthquakes located in Thessaly, as itpresents significant stability.

Sign in / Sign up

Export Citation Format

Share Document