tohoku earthquake
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2022 ◽  
Author(s):  
Onur BIYIK

Abstract This paper examines the Japanese International Bilateral Trade Flow (JIBTF) in relation to economic crises, such as the Tohoku earthquake, and focuses on changes in the Distribution Networks of JIBTF (DNoJ) concerning African countries and Japanese Major Trade Partners (JMTP). The Harmonized System 6-digit level (“total” and product level) panel data from 2001 to 2019 are analyzed by employing the (structural) gravity method. First, the results of the study find that the Tohoku earthquake, compared to the 2008 crisis, has a stronger negative impact on the JIBTF and affects the DNoJ among Japanese trade partners. Second, the results prove that Japanese trade intention with African markets decreases relatively. In other words, exporting to African countries has a negative interaction effect after 2015. On the contrary, this interaction effect on JMTP comparatively increases; thus, Japan relocates its export to other markets such as JMTP. The Tohoku earthquake shaped the JIBTF to be more integrated with the Asia-Pacific and the EU regions, instead of African markets.JEL Classification Codes: F10, F14, C23, C24


2022 ◽  
Author(s):  
Onur BIYIK

Abstract This paper examines the Japanese International Bilateral Trade Flow (JIBTF) in relation to economic crises, such as the Tohoku earthquake, and focuses on changes in the Distribution Networks of JIBTF (DNoJ) concerning African countries and Japanese Major Trade Partners (JMTP). The Harmonized System 6-digit level (“total” and product level) panel data from 2001 to 2019 are analyzed by employing the (structural) gravity method. First, the results of the study find that the Tohoku earthquake, compared to the 2008 crisis, has a stronger negative impact on the JIBTF and affects the DNoJ among Japanese trade partners. Second, the results prove that Japanese trade intention with African markets decreases relatively. In other words, exporting to African countries has a negative interaction effect after 2015. On the contrary, this interaction effect on JMTP comparatively increases; thus, Japan relocates its export to other markets such as JMTP. The Tohoku earthquake shaped the JIBTF to be more integrated with the Asia-Pacific and the EU regions, instead of African markets.JEL Classification Codes: F10, F14, C23, C24


2021 ◽  
Vol 12 (2) ◽  
pp. 120-124
Author(s):  
Michael Timothy Tasliman ◽  
Hongsik Yun

On 11 March 2011, a great earthquake with magnitude 9.0 has occurred in Tohoku, Japan, more than 1,000 km from South Korea. In fact, seismicity rate in South Korea has increased since the 2011 Tohoku earthquake, although detailed evaluation of its effects on the Korean Peninsula remains incomplete. Now, the high precision space geodesy techniques play a key role in monitoring the crustal strain state and energy variation. This study attempts to evaluate crustal deformation around the Korean Strait after 2011 Tohoku earthquake through a detailed analysis recorded by GPS. Moreover, this study found a different fault characteristic in Japan affect the station displacement prior to GPS data observed among 2011 to 2012. After a year, the strain in Japan found in direction WNW-ESE, while in Korea found in direction WSW-ENE. This finding suggests the likelihood of the existence of a certain tectonic line between the southern part of Korea peninsula and Japan.


2021 ◽  
Author(s):  
Olga V. PAVLENKO

Abstract Source and site effects of 2003 Tokachi-oki earthquake (Japan, Mw~8.3) and their influence on the distribution of peak ground accelerations (PGA) in the near-fault zones are studied. Based on records of KiK-net vertical arrays, models of soil behavior are constructed, i.e. vertical distributions of stresses and strains induced in soil layers by strong motion. The method is used suggested by Pavlenko and Irikura and previously applied for studying soil behavior during 1995 Kobe, 2000 Tottori, and 2011 Tohoku earthquakes. During the Tokachi-oki earthquake, we did not find a widespread nonlinearity of soft soil behavior. Manifestations of soil nonlinearity were observed at sites closest to the source; at remote sites where high PGA were recorded, soil behavior was virtually linear, and shear moduli in soils increased till the moments of the highest intensity of motion, then decreased. The shapes of acceleration time histories at remote sites indicate directivity effects: seismic waves radiated by the crack tip during its propagation along a section of the fault plane came to the stations simultaneously. Soil hardening occurred at these sites that increased amplification and PGA on the surface. Similar effects were observed during 2011 Tohoku earthquake; evidently, they can occur during future strong earthquakes.


2021 ◽  
Vol 9 ◽  
Author(s):  
Seiji Tsuno

In this study, the on-site P-wave earthquake early warning (EEW) based on the site-specific spectral ratio of S-wave to P-wave to efficiently incorporate the site characteristics, which can potentially issue the earthquake warning by the time of Ts-p, was developed. The spectral ratio of S-wave to P-wave that are related to the source effects, the path effects, and the site effects are significantly affected by the site effects contrast to the source effects and the path effects in practical. At first, the on-site P-wave EEW method which multiplies a site-specific spectral ratio of S-wave to P-wave prepared in advance by P-wave observed in the real-time at seismic stations is applied to seismic data for moderate-sized earthquakes with a magnitude (Mj) of 5.0–6.0, occurred in the eastern Japan, observed at both the sedimentary basin site and the rock site. As a result, this method predicted well the observed S-wave in the single indicator of SI within the logarithmic standard deviation of 0.25 as well as in the frequency of more than 0.5 Hz. It is, also, confirmed that the site-specific spectral ratio of S-wave to P-wave at a seismic station was stably retrieved from 20 data samples at least. To investigate the applicability of this method to earthquake ground motions induced by a large-scaled earthquake, finally, this method is applied to seismic data during the 2011 off the Pacific coast of Tohoku earthquake, Japan (Mw 9.0). The prediction of S-wave using a time-window of 10 s after P-wave arrived, could not reproduce the observation with the underestimation; however, the prediction of S-wave using a time-window of more than 20 s containing P-wave propagated from an area generating strong motions in the fault, could reproduce the observation. Even in the case of the large-scaled earthquake, the on-site P-wave EEW method based on the site-specific spectral ratio of S-wave to P-wave at a seismic station availably works by using the gradually increasing time-windows after P-wave arrived in the single indicator of SI as well as in the frequency content, avoiding the mixture of S-wave into a part of P-wave.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Boris Maletckii ◽  
Elvira Astafyeva

AbstractEarthquakes are known to generate ionospheric disturbances that are commonly referred to as co-seismic travelling ionospheric disturbances (CTID). In this work, for the first time, we present a novel method that enables to automatically detect CTID in ionospheric GNSS-data, and to determine their spatio-temporal characteristics (velocity and azimuth of propagation) in near-real time (NRT), i.e., less than 15 min after an earthquake. The obtained instantaneous velocities allow us to understand the evolution of CTID and to estimate the location of the CTID source in NRT. Furthermore, also for the first time, we developed a concept of real-time travel-time diagrams that aid to verify the correlation with the source and to estimate additionally the propagation speed of the observed CTID. We apply our methods to the Mw7.4 Sanriku earthquake of 09/03/2011 and the Mw9.0 Tohoku earthquake of 11/03/2011, and we make a NRT analysis of the dynamics of CTID driven by these seismic events. We show that the best results are achieved with high-rate 1 Hz data. While the first tests are made on CTID, our method is also applicable for detection and determining of spatio-temporal characteristics of other travelling ionospheric disturbances that often occur in the ionosphere driven by many geophysical phenomena.


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