Near‐ and far‐field tsunamigenic effects on the <i>Z</i> component of the geomagnetic field during the Japanese event, 2011

Klausner, Virginia; Kherani, E. A.; Muella, M. T. A. H.

doi:10.1002/2015ja022173

Cited by 16 publications

(8 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Minami, Toh, & Tyler, 2015) have also been based on computational work examining effects of seadepth parameter on tsunami wave propagation characteristic at open seas and determine whether advection or diffusion is the dominant physical process in a particular area in the ocean. As evaluated by Klausner, Kherani, & Muella (2016), a combined work of both computational techniques and field observations for determining the vertical component b z of tsunami-induced signals revealed the same results obtained for separate considerations of nearand far-field distances from a tsunami source. Minami et al (2015) discussed the roles of ocean depth h in terms of a functional relationship between the external parameter (ocean diffusivity κ) and internal parameters (tsunami phase speed c and the complex speed of ocean waves c s ).…”

Section: Introductionmentioning

confidence: 52%

Tsunami-Magnetic Signals and Magnetic Anomaly Generated by Tsunami Wave Propagation at Open Seas

Prastowo

Cholifah

Ngkoimani

et al. 2017

JPFI

View full text Add to dashboard Cite

This research examines the generation of tsunami-induced magnetic signals, where local magnetic anomaly were measured as variations in the vertical bz and horizontal bH components of the secondary field. The maximum amplitudes of bz and bH were analytically estimated and compared to magnetogram provided by INTERMAGNET and BCMT for the 2010 Chilean, the 2011 Tohoku, the 2010 Mentawai and the 2004 Aceh tsunamis. For the first two cases, frozen-flux theory was used to estimate bz and bH where the phase lag between bz and bH was ?/2, relevant to time interval of T/4 between the two signals. For the Mentawai case, oceanic diffusion was unignored and bz significantly deviated from that calculated using the theory. However, the data from Mentawai where bz ? 2 nT were in good agreement with bz generated by large tsunamis occurring in regions near the equator and with magnetogram from the Aceh event.

show abstract

Section: Introductionmentioning

confidence: 52%

Tsunami-Magnetic Signals and Magnetic Anomaly Generated by Tsunami Wave Propagation at Open Seas

Prastowo

Cholifah

Ngkoimani

et al. 2017

JPFI

View full text Add to dashboard Cite

show abstract

“…Observations using VLF receivers detected tsunami‐induced perturbations in the lower atmosphere (Rozhnoi et al, ). Tsunami‐induced upper atmospheric perturbations have also been captured by satellite measurements of the thermospheric neutral density (Garcia et al, ), and the electromagnetic perturbations are identifiable as variations in the geomagnetic field recorded by ground‐based magnetometers (Klausner et al, ; Utada et al, ). In addition, OTH radars are shown to be capable of observing tsunami‐induced signatures (Coïsson et al, ), yet no observational demonstrations have been made.…”

Section: Summary Of Major Observational Resultsmentioning

confidence: 99%

Upper Atmospheric Responses to Surface Disturbances: An Observational Perspective

et al. 2019

View full text Add to dashboard Cite

We review observations on the coupling between Earth's surface disturbances and the upper atmosphere. In particular, we focus on the upper atmospheric responses to atmospheric acousticgravity waves generated during impulsive surface disturbance events including earthquakes, tsunamis, volcanic eruptions, and explosions. We review the theoretical background for the generation and propagation of atmospheric acoustic-gravity waves from surface disturbance events as well as of the ionospheric plasma response to such acoustic-gravity waves. We review a variety of observational techniques that have been successfully utilized to detect upper atmospheric perturbations induced by surface disturbances and summarize the state-of-the-art knowledge on the coupling processes learnt from these observations. Finally, we touch on some most recent advances in the field and propose directions for future research.Plain Language Summary Earthquakes, tsunamis, volcanic eruptions, and chemical and nuclear explosions on or under the ground create sudden and violent motions of the ground or ocean surface. While ground shakings during some massive earthquakes can be felt by people who live thousands of kilometers away from the epicenters, the shakings can also be detected from the atmosphere hundreds of kilometers above the ground (upper atmosphere). Similarly, tsunamis, volcanic eruptions, and explosions can have footprints in the upper atmosphere as well. These footprints have been successfully detected by a variety of observational techniques. This paper reviews the observational results and the current understanding of the physical mechanisms behind the coupling between the ground/ocean and the upper atmosphere. In addition, future research directions are proposed in order to address the open questions.

show abstract

“…This tool also decomposes the signal into distinctive frequency variation and acquire information localized in both frequency and space domain. This technique is used as alternative way to analyze seismogenic and tsunamigenic impact on the geomagnetic field (Klausner et al, 2014a(Klausner et al, , 2016a(Klausner et al, , 2016b. It develops visual inspection tough task which construct the wavelet function that depends upon the scale function.…”

Section: Methodologmentioning

confidence: 99%

“…Concept of wavelet was firstly introduced on 1980's for the analysis of seismic data, by Morlet et al (1982) and Morlet (1983). This tool is also famous in applied geomagnetic seismology (Klausner et al, 2014aand Klausner et al, 2016a, Klausner et al, 2016b, Klausner et al, 2017. The amplitude of the wavelet coefficient can be used as a gauge of local uniformity of a signal as described in Mallat (1991).…”

Section: Introductionmentioning

confidence: 99%

Application of wavelet for seismic wave analysis in Kathmandu Valley after the 2015 Gorkha earthquake, Nepal

Adhikari

Dahal²,

Karki³

et al. 2020

Geoenviron Disasters

Self Cite

View full text Add to dashboard Cite

In this paper, we estimate the seismogenic energy during the Nepal Earthquake (25 April 2015) and studied the ground motion time-frequency characteristics in Kathmandu valley. The idea to analyze time-frequency characteristic of seismogenic energy signal is based on wavelet transform which we employed here. Wavelet transform has been used as a powerful signal analysis tools in various fields like compression, time-frequency analysis, earthquake parameter determination, climate studies, etc. This technique is particularly suitable for non-stationary signal. It is well recognized that the earthquake ground motion is a non-stationary random process. In order to characterize a non-stationary random process, it is required immeasurable samples in the mathematical sense. The wavelet transformation procedures that we follow here helps in random analyses of linear and non-linear structural systems, which are subjected to earthquake ground motion. The manners of seismic ground motion are characterized through wavelet coefficients associated to these signals. Both continuous wavelet transform (CWT) and discrete wavelet transform (DWT) techniques are applied to study ground motion in Kathmandu Valley in horizontal and vertical directions. These techniques help to point out the long-period ground motion with site response. We found that the long-period ground motions have enough power for structural damage. Comparing both the horizontal and the vertical motion, we observed that the most of the high amplitude signals are associated with the vertical motion: the high energy is released in that direction. It is found that the seismic energy is damped soon after the main event; however the period of damping is different. This can be seen on DWT curve where square wavelet coefficient is high at the time of aftershock and the value decrease with time. In other words, it is mostly associated with the arrival of Rayleigh waves. We concluded that long-period ground motions should be studied by earthquake engineers in order to avoid structural damage during the earthquake. Hence, by using wavelet technique we can specify the vulnerability of seismically active region and local topological features out there.

show abstract

Near‐ and far‐field tsunamigenic effects on the Z component of the geomagnetic field during the Japanese event, 2011

Cited by 16 publications

References 24 publications

Tsunami-Magnetic Signals and Magnetic Anomaly Generated by Tsunami Wave Propagation at Open Seas

Tsunami-Magnetic Signals and Magnetic Anomaly Generated by Tsunami Wave Propagation at Open Seas

Upper Atmospheric Responses to Surface Disturbances: An Observational Perspective

Application of wavelet for seismic wave analysis in Kathmandu Valley after the 2015 Gorkha earthquake, Nepal

Contact Info

Product

Resources

About