Experiments of Earthquake Early Warning to Expressway Drivers Using Synchronized Driving Simulators

2009 ◽  
Vol 25 (2) ◽  
pp. 347-360 ◽  
Author(s):  
Yoshihisa Maruyama ◽  
Fumio Yamazaki ◽  
Masato Sakaya
Keyword(s):  
Early Warning ◽  
Side Effect ◽  
General Public ◽  
Traffic Accidents ◽  
Earthquake Early Warning ◽  
Japan Meteorological Agency ◽  
Test Cases ◽  
Driving Simulators ◽  
The Public ◽  
Close Proximity

To reduce the casualties and impacts resulting from earthquakes, the Japan Meteorological Agency (JMA) introduced its earthquake early warning (EEW) system to the general public on 1 October 2007. Interestingly, a side effect of the system is an anticipated increase in traffic accidents that may occur because the EEW transmission will not be received by all drivers. Consequently, the effects of an EEW are investigated using three synchronized driving simulators to replicate the conditions of three cars traveling in close proximity on an expressway. When the EEW was received by all cars, the drivers behaved properly, and no problems occurred. When an EEW was received by just one car, however, some drivers reduced speed immediately, and accidents resulted in two out of 14 test cases. These experiments show the necessity of educating the public on how to respond if an EEW is received while driving on an expressway. In such situations, activating hazard lights and reducing speed gradually is suggested to avoid traffic accidents.

EFFECTS OF EARTHQUAKE EARLY WARNING TO EXPRESSWAY DRIVERS BASED ON DRIVING SIMULATOR EXPERIMENTS

2009 ◽  
Vol 03 (04) ◽  
pp. 261-272 ◽  
Author(s):  
YOSHIHISA MARUYAMA ◽  
MASATO SAKAYA ◽  
FUMIO YAMAZAKI
Keyword(s):  
Public Education ◽  
Early Warning ◽  
General Public ◽  
Traffic Accidents ◽  
Driving Simulator ◽  
Earthquake Early Warning ◽  
Japan Meteorological Agency ◽  
Driving Simulators ◽  
Seismic Motion

To reduce casualties and troubles due to earthquakes, Japan Meteorological Agency introduced earthquake early warning (EEW) to general public on 1 October 2007. However, the possibility that EEW induces traffic accidents exists because EEW through car radio may not be transmitted to all the expressway drivers. Hence, the effects of EEW were investigated based on driving simulator experiments. Two kinds of experiments were performed in this study. First, single driving simulator was employed to reveal the effects of EEW on expressways. The reactions of drivers with/without warning are compared in avoiding an obstacle induced by seismic motion. Second, three synchronized driving simulators, simulating three cars running together on an expressway, were employed. When EEW was transmitted to only one car, some drivers reduced speed suddenly, and accidents occurred in two cases out of 14 tests. These experiments show the necessity of public education how to react an EEW on expressways. Turning on the hazard lights after receiving an EEW and then reducing speed gradually is suggested to avoid traffic accidents.

The Extended Integrated Particle Filter Method (IPFx) as a High-Performance Earthquake Early Warning System

2021 ◽  
Author(s):  
Masumi Yamada ◽  
Koji Tamaribuchi ◽  
Stephen Wu
Keyword(s):  
Particle Filter ◽  
Early Warning ◽  
Seismic Intensity ◽  
Earthquake Early Warning ◽  
Japan Meteorological Agency ◽  
Estimation Accuracy ◽  
Filter Method ◽  
Source Estimation ◽  
Single Station ◽  
Seismic Networks

ABSTRACT An earthquake early warning (EEW) system rapidly analyzes seismic data to report the occurrence of an earthquake before strong shaking is felt at a site. In Japan, the integrated particle filter (IPF) method, a new source-estimation algorithm, was recently incorporated into the EEW system to improve the source-estimation accuracy during active seismicity. The problem of the current IPF method is that it uses the trigger information computed at each station in a specific format as the input and is therefore applicable to only limited seismic networks. This study proposes the extended IPF (IPFx) method to deal with continuous waveforms and merge all Japanese real-time seismic networks into a single framework. The new source determination algorithm processes seismic waveforms in two stages. The first stage (single-station processing) extracts trigger and amplitude information from continuous waveforms. The second stage (network processing) accumulates information from multiple stations and estimates the location and magnitude of ongoing earthquakes based on Bayesian inference. In 10 months of continuous online experiments, the IPFx method showed good performance in detecting earthquakes with maximum seismic intensity ≥3 in the Japan Meteorological Agency (JMA) catalog. By merging multiple seismic networks into a single EEW system, the warning time of the current EEW system can be improved further. The IPFx method provides accurate shaking estimation even at the beginning of event detection and achieves seismic intensity error <0.25  s after detecting an event. This method correctly avoided two major false alarms on 5 January 2018 and 30 July 2020. The IPFx method offers the potential of expanding the JMA IPF method to global seismic networks.

Practical Site-Specific Earthquake Early Warning Application

2009 ◽  
Vol 4 (4) ◽  
pp. 579-587 ◽  
Author(s):  
Katsuhisa Kanda ◽  
◽  
Tadashi Nasu ◽  
Masamitsu Miyamura
Keyword(s):  
Early Warning ◽  
Estimation Error ◽  
Seismic Intensity ◽  
Earthquake Early Warning ◽  
P Wave ◽  
Japan Meteorological Agency ◽  
Estimation Accuracy ◽  
Intensity Estimation ◽  
Site Specific ◽  
Wide Range

Real-time hazard mitigation we have developed using earthquake early warning (EEW) (1) enhances seismic intensity estimation accuracy and (2) extends the interval between when an EEW is issued and when strong tremors arrive. We accomplished the first point (enhancing seismic intensity estimation) by reducing estimation error to less than that commonly used based on an attenuation relationship and soil amplification factor by considering source-location and wave propagation path differences based on site-specific empiricism. We accomplished the second point (shortening the time between warnings and when tremors arrive) using a high-speed, reliable communication network for receiving EEW information from the Japan Meteorological Agency (JMA) and quickly transmitting warning signals to users. In areas close to quake epicenters, however, warnings may not arrive before the arrival of strong ground motions. The on-site warning system we developed uses P-wave pickup sensors that detect P-wave arrival at a site and predict seismic intensity of subsequent S-waves. We confirmed the on-site warning prototype’s feasibility based on numerical simulation and observation. We also developed an integration server for combining on-site warnings with JMA information to be applied to earthquakes over a wide range of distances. We installed a practical prototype at a construction site near the 2008 Iwate-Miyagi Inland Earthquake epicenter to measure its aftershocks because JMA EEW information was too late to use against the main shock. We obtained good aftershock results, confirming the prototype’s applicability and accuracy. Integration server combination logic was developed for manufacturing sites requiring highly robust, reliable control.

scholarly journals Brief communication: Appropriate messaging is critical for effective earthquake early warning systems

2021 ◽  
Author(s):  
Meng Zhang ◽  
Xue Qiao ◽  
Barnabas C. Seyler ◽  
Baofeng Di ◽  
Yuan Wang ◽  
...  
Keyword(s):  
Early Warning ◽  
Communication Channels ◽  
Early Warning Systems ◽  
Earthquake Early Warning ◽  
Warning Systems ◽  
The Public ◽  
Earthquake Early Warning Systems ◽  
Great Progress ◽  
And Training

Abstract. The earthquake early warning systems (EEWSs) in China have achieved great progress, with warning alerts being successfully delivered to the public in some regions. We examined the performance of the EEWS in China's Sichuan Province during the 2019 Changning Earthquake. Although its technical effectiveness was tested with the first alert released 10 s after the earthquake, we found that a big gap existed between the EEWS's message and the public's response. We highlight the importance of EEWS alert effectiveness and public participation for long-term resiliency, such as delivering useful alert messages through appropriate communication channels and training people to understand and properly respond.

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.

scholarly journals Developments of the Nationwide Earthquake Early Warning System in Japan After the 2011 Mw9.0 Tohoku-Oki Earthquake

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuki Kodera ◽  
Naoki Hayashimoto ◽  
Koji Tamaribuchi ◽  
Keishi Noguchi ◽  
Ken Moriwaki ◽  
...  
Keyword(s):  
Point Source ◽  
Ground Motion ◽  
Early Warning ◽  
Prediction Accuracy ◽  
Ground Motions ◽  
Earthquake Early Warning ◽  
Japan Meteorological Agency ◽  
Motion Prediction ◽  
Ground Motion Prediction ◽  
Strong Ground

In Japan, the nationwide earthquake early warning (EEW) system has been being operated by the Japan Meteorological Agency (JMA) since 2007, disseminating information on imminent strong ground motion to the general public and advanced technical users. In the beginning of the operation, the system ran based mainly on standard source-based algorithms with a point-source location estimate and ground motion prediction equation. The point-source algorithms successfully provided ground motion predictions with high accuracy during the initial operation; however, the 2011 Mw9.0 Tohoku-Oki earthquake and the subsequent intense aftershock and triggered earthquake activities underscored the weaknesses of the source-based approach. In this paper, we summarize major system developments after the Tohoku-Oki event to overcome the limits of the standard point-source algorithms and to enhance the EEW performance further. In addition, we evaluate how the system performance was influenced by the updates. One of significant improvements in the JMA EEW system was the implementation of two new ground motion prediction methods: the integrated particle filter (IPF) and propagation of local undamped motion (PLUM) algorithms. IPF is a robust point-source algorithm based on the Bayesian inference, and PLUM is a wavefield-based algorithm that predicts ground motions directly from observed shakings. Another notable update was the incorporation of new observation facilities including S-net, a large-scale ocean bottom seismometer network deployed along the Japan and Kuril trenches. The prediction accuracy and warning issuance performance analysis for the updated JMA EEW system showed that IPF improved the source-based ground motion prediction accuracy and reduced the risk of issuing overpredicted warnings. PLUM made the system less likely to underpredict strong ground motions and improved the warning issuance timeliness. The detection time analysis for the S-net incorporation suggested that S-net enabled the system to issue the first EEW report earlier than before the S-net incorporation for earthquakes around the Japan and Kuril trenches. Those findings indicate that the JMA EEW system has made substantial progress both on software and hardware aspects over the 10 years after the Tohoku-Oki earthquake.

Study on the Changes in People’s Consciousness Regarding the Earthquake Early Warning Before and After the Great East Japan Earthquake – Analysis Based on Regular Disaster Information Survey Results –

2013 ◽  
Vol 8 (sp) ◽  
pp. 792-801
Author(s):  
Miho Ohara ◽  
◽  
Atsushi Tanaka ◽  
Keyword(s):  
Early Warning ◽  
General Public ◽  
Earthquake Early Warning ◽  
Great East Japan Earthquake ◽  
Secular Changes ◽  
Study Results ◽  
Disaster Information ◽  
Before And After ◽  
Survey Results ◽  
Early Warnings

In Japan, earthquake early warnings (EEWs), also known as alerts, have been broadcast to the general public since October 1, 2007. Issuance times of EEWincreased drastically after the Great East Japan Earthquake, and citizens had much more frequent experience with EEWs. This study analyzes secular changes in rates of recognition and reception experiences of EEW. It also analyzes awareness regarding EEW accuracy by comparing study results with EEW issuance history nationwide. Secular changes in the expectations of the general public regarding EEWs are also clarified.

scholarly journals Earthquake Early Warning in Japan: Warning the General Public and Future Prospects

2009 ◽  
Vol 80 (5) ◽  
pp. 717-726 ◽  
Author(s):  
O. Kamigaichi ◽  
M. Saito ◽  
K. Doi ◽  
T. Matsumori ◽  
S. Tsukada ◽  
...  
Keyword(s):  
Early Warning ◽  
General Public ◽  
Earthquake Early Warning ◽  
Future Prospects
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