Earthquake Early Warning and Tsunami Warning of the Japan Meteorological Agency, and Their Performance in the 2011 off the Pacific Coast of Tohoku Earthquake ( $${M}_{{\mathrm{w}}}$$ 9.0)

2014 ◽  
pp. 1-28 ◽  
Author(s):  
M. Hoshiba ◽  
T. Ozaki
Keyword(s):  
Early Warning ◽  
Pacific Coast ◽  
Tohoku Earthquake ◽  
Earthquake Early Warning ◽  
Tsunami Warning ◽  
Japan Meteorological Agency ◽  
The Pacific

JMA’s Tsunami Warning for the 2011 Great Tohoku Earthquake and Tsunami Warning Improvement Plan

2012 ◽  
Vol 7 (sp) ◽  
pp. 439-445 ◽  
Author(s):  
Tomoaki Ozaki ◽  
Keyword(s):  
Pacific Coast ◽  
Early Stage ◽  
Tohoku Earthquake ◽  
Lessons Learned ◽  
Tsunami Warning ◽  
Japan Meteorological Agency ◽  
Improvement Plan ◽  
The Pacific

The Japan Meteorological Agency (JMA) issued a timely tsunami warning three minutes after the 2011 off the Pacific coast of Tohoku Earthquake (the Great Tohoku Earthquake) occurred at 14:49 (JST) on March 11, 2011. However, predicted tsunami heights at the early stage were greatly underestimated. Based on lessons learned from this earthquake, the JMA plans to improve its tsunami warning.

scholarly journals Outline of the 2011 off the Pacific coast of Tohoku Earthquake (M w 9.0) —Earthquake Early Warning and observed seismic intensity—

2011 ◽  
Vol 63 (7) ◽  
pp. 547-551 ◽  
Author(s):  
Mitsuyuki Hoshiba ◽  
Kazuhiro Iwakiri ◽  
Naoki Hayashimoto ◽  
Toshihiro Shimoyama ◽  
Kazuyuki Hirano ◽  
...  
Keyword(s):  
Early Warning ◽  
Pacific Coast ◽  
Tohoku Earthquake ◽  
Seismic Intensity ◽  
Earthquake Early Warning ◽  
The Pacific

scholarly journals Subsidence by liquefaction-fluidization in man-made strata around Tokyo bay, Japan: from geological survey on damaged part at the 2011 off the Pacific Coast of Tohoku Earthquake

2015 ◽  
Vol 372 ◽  
pp. 221-226
Author(s):  
O. Kazaoka ◽  
S. Kameyama ◽  
K. Shigeno ◽  
Y. Suzuki ◽  
M. Morisaki ◽  
...  
Keyword(s):  
Pacific Coast ◽  
Tohoku Earthquake ◽  
Geological Survey ◽  
Japan Meteorological Agency ◽  
Tokyo Bay ◽  
Great Earthquake ◽  
Reclaimed Land ◽  
Chiba Prefecture ◽  
Detailed Classification ◽  
The Pacific

Abstract. Geological disaster by liquefaction-fluidization happened on southern part of the Quaternary Paleo-Kanto submarine basin at the 2011 Earthquake off the Pacific Coast of Tohoku. Liquefaction-fluidization phenomena occurred mainly in man-made strata over shaking 5+ intensity of Japan Meteorological Agency scale. Many subsided spots, 10–50 m width, 20–100 m length and less than 1 m depth, by liquefaction-fluidization distributed on reclaimed land around northern Tokyo bay. Large amount of sand and groundwater spouted out in the terrible subsided parts. But there are little subsidence and no jetted sand outside the terrible subsided part. Liquefaction-fluidization damaged part at the 1987 earthquake east off Chiba prefecture re-liquefied and fluidized in these parts at the 2011 great earthquake. The damaged area were more wide on the 2011 earthquake than the 1987 quake. Detailed classification maps of subsidence by liquefaction-fluidization on the 2011 grate earthquake were made by fieldwork in Chiba city around Tokyo bay. A mechanism of subsidence by liquefaction-fluidization in man-made strata was solved by geological survey with continuous large box cores on the ACE Liner and large relief peals of the cores at a typical subsided part.

Event Detection Performance of the PLUM Earthquake Early Warning Algorithm in Southern California

2019 ◽  
Vol 109 (4) ◽  
pp. 1524-1541 ◽  
Author(s):  
Elizabeth S. Cochran ◽  
Julian Bunn ◽  
Sarah E. Minson ◽  
Annemarie S. Baltay ◽  
Deborah L. Kilb ◽  
...  
Keyword(s):  
Los Angeles ◽  
Ground Motion ◽  
Early Warning ◽  
Southern California ◽  
Ground Motions ◽  
Tohoku Earthquake ◽  
Prediction Equation ◽  
Earthquake Early Warning ◽  
Japan Meteorological Agency ◽  
Origin Time

Abstract We test the Japanese ground‐motion‐based earthquake early warning (EEW) algorithm, propagation of local undamped motion (PLUM), in southern California with application to the U.S. ShakeAlert system. In late 2018, ShakeAlert began limited public alerting in Los Angeles to areas of expected modified Mercalli intensity (IMMI) 4.0+ for magnitude 5.0+ earthquakes. Most EEW systems, including ShakeAlert, use source‐based methods: they estimate the location, magnitude, and origin time of an earthquake from P waves and use a ground‐motion prediction equation to identify regions of expected strong shaking. The PLUM algorithm uses observed ground motions directly to define alert areas and was developed to address deficiencies in the Japan Meteorological Agency source‐based EEW system during the 2011 Mw 9.0 Tohoku earthquake sequence. We assess PLUM using (a) a dataset of 193 magnitude 3.5+ earthquakes that occurred in southern California between 2012 and 2017 and (b) the ShakeAlert testing and certification suite of 49 earthquakes and other seismic signals. The latter suite includes events that challenge the current ShakeAlert algorithms. We provide a first‐order performance assessment using event‐based metrics similar to those used by ShakeAlert. We find that PLUM can be configured to successfully issue alerts using IMMI trigger thresholds that are lower than those implemented in Japan. Using two stations, a trigger threshold of IMMI 4.0 for the first station and a threshold of IMMI 2.5 for the second station PLUM successfully detect 12 of 13 magnitude 5.0+ earthquakes and issue no false alerts. PLUM alert latencies were similar to and in some cases faster than source‐based algorithms, reducing area that receives no warning near the source that generally have the highest ground motions. PLUM is a simple, independent seismic method that may complement existing source‐based algorithms in EEW systems, including the ShakeAlert system, even when alerting to light (IMMI 4.0) or higher ground‐motion levels.

Differences in Subjective Estimation of Risks and Assessment for the Modified Tsunami Warning System by the Japan Meteorological Agency Among University Students Located in Damaged and Non-Damaged Prefectures Around the Period of the 2011 off Pacific Coast of Tohoku Earthquake

2014 ◽  
Vol 9 (4) ◽  
pp. 571-578 ◽  
Author(s):  
Erina Gyoba ◽  
Keyword(s):  
University Students ◽  
Pacific Coast ◽  
Damage Zone ◽  
Warning System ◽  
Tohoku Earthquake ◽  
Tsunami Warning ◽  
Disaster Mitigation ◽  
Japan Meteorological Agency ◽  
Tsunami Height ◽  
Tsunami Warning System

The Japan Meteorological Agency (JMA) released a new version of tsunami warning system using three qualitative expressions for tsunami height. Understanding disaster mitigation information requires adequate knowledge on disaster occurrence mechanisms and precise action in emergencies. We surveyed differences in understanding and assessing tsunami warning information among university students in two prefectures – one damaged by the 2011 off Pacific Coast of Tohoku Earthquake and the other outside of the damage zone. Results revealed that those outside of the damage zone tended to estimate tsunami heights as higher than those inside the damage zone when reading qualitative tsunami heights in the JMA’s new tsunami warning version. They also tended to need more concrete, precise information to understand appropriate evacuation procedures provided by public institutions, including the JMA.

Reproduction Analysis of Short-circuit between Transmission Lines during the 2011 Off the Pacific Coast of Tohoku Earthquake and a Consideration of the cause of the Event

2014 ◽  
Vol 134 (8) ◽  
pp. 732-742 ◽  
Author(s):  
Hiroshi Ohta ◽  
Akio Kawahara ◽  
Hideharu Nakamura ◽  
Motoyuki Yamazaki ◽  
Eijiro Hongo
Keyword(s):  
Transmission Lines ◽  
Pacific Coast ◽  
Short Circuit ◽  
Tohoku Earthquake ◽  
The Pacific
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