Earthquake early warning for the 2016 Kumamoto earthquake: performance evaluation of the current system and the next-generation methods of the Japan Meteorological Agency

Kodera, Yuki; Saitou, Jun; Hayashimoto, Naoki; Adachi, Shimpei; Morimoto, Masahiko; Nishimae, Yuji; Hoshiba, Mitsuyuki

doi:10.1186/s40623-016-0567-1

Cited by 54 publications

(49 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The JMA EEW system (Hoshiba et al 2008) issued a first public warning 8 s after the origin of the Kumamoto main shock, which was 3.9 s after the event was detected (Kodera et al 2016). Although the initial magnitude was underestimated as M JMA 5.9 (∼M5.7, using updated relations by Oth et al 2010;Oth, 2017, private communication), it was large enough to meet the criteria for issuing a warning.…”

Section: R E S U Lt Smentioning

confidence: 99%

“…The smaller M5.5 earthquake at about 16:25:38 UTC, which was likely triggered by the main shock (Kodera et al 2016;Hoshiba 2017), causes a secondary patch of significant high-frequency shaking at about 80 km northeast of the M7.0 Kumamoto epicentre (Fig. 3f).…”

Section: R E S U Lt Smentioning

confidence: 99%

“…This second earthquake (∼M JMA 5.7; Kodera et al 2016) occurred about 32-34 s after the M7.0 Kumamoto earthquake; its waveforms are mostly hidden in the main shock coda, and the event is visible mainly in the high-frequency band (Hoshiba 2017).…”

Section: R E S U Lt Smentioning

confidence: 99%

“…Although the initial magnitude was underestimated as M JMA 5.9 (∼M5.7, using updated relations by Oth et al 2010;Oth, 2017, private communication), it was large enough to meet the criteria for issuing a warning. Five seconds later, the magnitude was upgraded to M JMA 6.9 (Kodera et al 2016;∼M6.6). Although the second M JMA 5.7 (∼M5.5) event at 80 km distance did not affect the hypocentre and magnitude estimates for the main shock, the system underpredicted the seismic intensity (4 JMA scale) in the area around the secondary earthquake, which was observed as 6 L (Kodera et al 2016).…”

Section: R E S U Lt Smentioning

confidence: 99%

“…Five seconds later, the magnitude was upgraded to M JMA 6.9 (Kodera et al 2016;∼M6.6). Although the second M JMA 5.7 (∼M5.5) event at 80 km distance did not affect the hypocentre and magnitude estimates for the main shock, the system underpredicted the seismic intensity (4 JMA scale) in the area around the secondary earthquake, which was observed as 6 L (Kodera et al 2016).…”

Section: R E S U Lt Smentioning

confidence: 99%

See 4 more Smart Citations

FinDer v.2: Improved real-time ground-motion predictions for M2–M9 with seismic finite-source characterization

Böse¹,

Smith

Felizardo

et al. 2017

Geophysical Journal International

View full text Add to dashboard Cite

S U M M A R YRecent studies suggest that small and large earthquakes nucleate similarly, and that they often have indistinguishable seismic waveform onsets. The characterization of earthquakes in real time, such as for earthquake early warning, therefore requires a flexible modeling approach that allows a small earthquake to become large as fault rupture evolves over time. Here, we present a modeling approach that generates a set of output parameters and uncertainty estimates that are consistent with both small/moderate (≤M6.5) and large earthquakes (>M6.5) as is required for a robust parameter interpretation and shaking forecast. Our approach treats earthquakes over the entire range of magnitudes (>M2) as finite line-source ruptures, with the dimensions of small earthquakes being very small (<100 m) and those of large earthquakes exceeding several tens to hundreds of kilometres in length. The extent of the assumed line source is estimated from the level and distribution of high-frequency peak acceleration amplitudes observed in a local seismic network. High-frequency motions are well suited for this approach, because they are mainly controlled by the distance to the rupturing fault. Observed ground-motion patterns are compared with theoretical templates modeled from empirical ground-motion prediction equations to determine the best line source and uncertainties. Our algorithm extends earlier work by Böse et al. for large finite-fault ruptures. This paper gives a detailed summary of the new algorithm and its offline performance for the 2016 M7.0 Kumamoto, Japan and 2014 M6.0 South Napa, California earthquakes, as well as its performance for about 100 real-time detected local earthquakes (2.2 ≤ M ≤ 5.1) in California. For most events, both the rupture length and the strike are well constrained within a few seconds (<10 s) of the event origin. In large earthquakes, this could allow for providing warnings of up to several tens of seconds. The algorithm could also be useful for resolving fault plane ambiguities of focal mechanisms and identification of rupturing faults for earthquakes as small as M2.5.

show abstract

Section: R E S U Lt Smentioning

confidence: 99%

Section: R E S U Lt Smentioning

confidence: 99%

Section: R E S U Lt Smentioning

confidence: 99%

Section: R E S U Lt Smentioning

confidence: 99%

Section: R E S U Lt Smentioning

confidence: 99%

See 3 more Smart Citations

FinDer v.2: Improved real-time ground-motion predictions for M2–M9 with seismic finite-source characterization

Böse¹,

Smith

Felizardo

et al. 2017

Geophysical Journal International

View full text Add to dashboard Cite

show abstract

Real‐Time Detection of Rupture Development: Earthquake Early Warning Using P Waves From Growing Ruptures

Kodera

2018

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

Large earthquakes with long rupture durations emit P wave energy throughout the rupture period. Incorporating late‐onset P waves into earthquake early warning (EEW) algorithms could contribute to robust predictions of strong ground motion. Here I describe a technique to detect in real time P waves from growing ruptures to improve the timeliness of an EEW algorithm based on seismic wavefield estimation. The proposed P wave detector, which employs a simple polarization analysis, successfully detected P waves from strong motion generation areas of the 2011 Mw 9.0 Tohoku‐oki earthquake rupture. An analysis using 23 large (M ≥ 7) events from Japan confirmed that seismic intensity predictions based on the P wave detector significantly increased lead times without appreciably decreasing the prediction accuracy. P waves from growing ruptures, being one of the fastest carriers of information on ongoing rupture development, have the potential to improve the performance of EEW systems.

show abstract

How “good” are real‐time ground motion predictions from Earthquake Early Warning systems?

Meier

2017

JGR Solid Earth

View full text Add to dashboard Cite

Real‐time ground motion alerts, as can be provided by Earthquake Early Warning (EEW) systems, need to be both timely and sufficiently accurate to be useful. Yet how timely and how accurate the alerts of existing EEW algorithms are is often poorly understood. In part, this is because EEW algorithm performance is usually evaluated not in terms of ground motion prediction accuracy and timeliness but in terms of other metrics (e.g., magnitude and location estimation errors), which do not directly reflect the usefulness of the alerts from an end user perspective. Here we attempt to identify a suite of metrics for EEW algorithm performance evaluation that directly quantify an algorithm's ability to identify target sites that will experience ground motion above a critical (user‐defined) ground motion threshold. We process 15,553 recordings from 238 earthquakes with M > 5 (mostly from Japan and southern California) in a pseudo‐real‐time environment and investigate two end‐member EEW methods. We use the metrics to highlight both the potential and limitations of the two algorithms and to show under which circumstances useful alerts can be provided. Such metrics could be used by EEW algorithm developers to convincingly demonstrate the added value of new algorithms or algorithm components. They can complement existing performance metrics that quantify other relevant aspects of EEW algorithms (e.g., false event detection rates) for a comprehensive and meaningful EEW performance analysis.

show abstract

Earthquake early warning for the 2016 Kumamoto earthquake: performance evaluation of the current system and the next-generation methods of the Japan Meteorological Agency

Cited by 54 publications

References 12 publications

FinDer v.2: Improved real-time ground-motion predictions for M2–M9 with seismic finite-source characterization

FinDer v.2: Improved real-time ground-motion predictions for M2–M9 with seismic finite-source characterization

Real‐Time Detection of Rupture Development: Earthquake Early Warning Using P Waves From Growing Ruptures

How “good” are real‐time ground motion predictions from Earthquake Early Warning systems?

Contact Info

Product

Resources

About