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 Study on Site Amplification Factor Correction for Earthquake Early Warning System

2019 ◽  
Author(s):  
Quancai Xie ◽  
Qiang Ma ◽  
Jingfa Zhang ◽  
Haiying Yu
Keyword(s):  
Early Warning ◽  
Amplification Factor ◽  
Spectral Ratio ◽  
Site Amplification ◽  
Seismic Intensity ◽  
Earthquake Early Warning ◽  
Filter Method ◽  
Recursive Filter ◽  
Earthquake Early Warning System ◽  
Site Amplification Factor

Abstract. The site amplification factor was usually considered as scalar values, such as amplification of peak ground acceleration or peak ground velocity, increments of seismic intensity in the conventional earthquake early warning system. This paper focus on evaluation of infinite impulse recursive filter method that could produce frequency-dependent site amplification and compare the performance of the scalar value method with the infinite impulse recursive filter method. Firstly, the strong motion data of IBRH10 and IBRH19 of Kiban Kyoshin network (Kik-net）from 2004 to 2012 were processed and selected carefully. The relative spectral ratio of IBRH10 surface acceleration to IBRH10 borehole acceleration, the relative spectral ratio of IBRH19 surface acceleration to IBRH19 borehole acceleration, the relative spectral ratio the IBRH10 surface and borehole acceleration to the IBRH19 surface and borehole acceleration were calculated using the traditional spectral ratio method. Secondly, the relative spectral ratio were modelled using the infinite impulse recursive filter method. The simulated IBRH19 surface acceleration and Fourier spectrum were obtained by filtering the IBRH19 borehole data. The seismic intensity residual were calculated for both the observation and simulation data, it shows that 98.6 % of these seismic intensity residuals are less than 0.5, 100 % of these seismic intensity residuals are less than 1. Similarly, the simulated IBRH10 Surface acceleration and Fourier spectrum were obtained by filtering the IBRH19 surface acceleration time series. The seismic intensity residual were calculated for both the observation data and the simulation data. The statistical data shows that 69.7 % of these seismic intensity residuals are less than 0.5, 98.1 % of these seismic intensity residuals are less than 1. Through these comparisons, we can find that these simulations show better performance than the ARV method and station correction method. It also shows good performance than the average level and the highest level of all the 11 years Japan Meteorological Agency (JMA) earthquake early warning system. Thirdly, compare different simulation cases, it can be easily found that this method could produce different amplification factor for different earthquakes. It could produce the frequency-depend site amplification factor. It highly improve the situation that the scalar value site amplification methods which could not produce different amplification factor for different earthquakes. This method pays attention to the amplitude and ignore the phase characteristic, this problem may be improved by the seismic interferometry method. This paper makes deep evaluation of the infinite impulse recursive filter method. Although there are some problems needed to consider carefully and solve, it shows good potential to be used in the future earthquake early warning systems for more accuracy modelling the site amplification factor.

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.

On the estimation of seismic intensity in earthquake early warning systems

2008 ◽  
Vol 35 (7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Shunroku Yamamoto ◽  
Paul Rydelek ◽  
Shigeki Horiuchi ◽  
Changjiang Wu ◽  
Hiromitsu Nakamura
Keyword(s):  
Early Warning ◽  
Early Warning Systems ◽  
Seismic Intensity ◽  
Earthquake Early Warning ◽  
Warning Systems ◽  
Earthquake Early Warning Systems

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.

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.

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