Finite-Fault Rupture Detector (<i>FinDer</i>): Going Real-Time in Californian<i>ShakeAlert</i>Warning System

Böse, Maren; Felizardo, C.; Heaton, Thomas H.

doi:10.1785/0220150154

Cited by 55 publications

(33 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, once earthquake initiation is identified on a continental fault whose long‐term propagation direction is known, it seems possible to anticipate in which direction earthquake slip may increase and rupture may accelerate. This information can be constrained in real time and could critically contribute to earthquake early warning systems, helping anticipate sites of largest ground motions and warn populations on the way of the growing rupture [e.g., Böse and Heaton , ; Böse et al ., , ].…”

Section: Discussionmentioning

confidence: 99%

Location of largest earthquake slip and fast rupture controlled by along‐strike change in fault structural maturity due to fault growth

et al. 2016

View full text Add to dashboard Cite

Earthquake slip distributions are asymmetric along strike, but the reasons for the asymmetry are unknown. We address this question by establishing empirical relations between earthquake slip profiles and fault properties. We analyze the slip distributions of 27 large continental earthquakes in the context of available information on their causative faults, in particular on the directions of their long‐term lengthening. We find that the largest slips during each earthquake systematically occurred on that half of the ruptured fault sections most distant from the long‐term fault propagating tips, i.e., on the most mature half of the broken fault sections. Meanwhile, slip decreased linearly over most of the rupture length in the direction of long‐term fault propagation, i.e., of decreasing structural maturity along strike. We suggest that this earthquake slip asymmetry is governed by along‐strike changes in fault properties, including fault zone compliance and fault strength, induced by the evolution of off‐fault damage, fault segmentation, and fault planarity with increasing structural maturity. We also find higher rupture speeds in more mature rupture sections, consistent with predicted effects of low‐velocity damage zones on rupture dynamics. Since the direction(s) of long‐term fault propagation can be determined from geological evidence, it might be possible to anticipate in which direction earthquake slip, once nucleated, may increase, accelerate, and possibly lead to a large earthquake. Our results could thus contribute to earthquake hazard assessment and Earthquake Early Warning.

show abstract

Section: Discussionmentioning

confidence: 99%

Location of largest earthquake slip and fast rupture controlled by along‐strike change in fault structural maturity due to fault growth

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The FinDer algorithm (Böse et al, 2012;Böse et al, 2015;Böse et al, 2018) rapidly determines line source models of small (M3) to large (M9) earthquakes by matching the spatial distribution of observed ground motion amplitudes in a seismic network with theoretical template maps. These templates are precalculated from empirical ground-motion prediction equations (GMPEs) for line sources of different lengths and magnitudes, and they are rotated to constrain the strike of the earthquake fault rupture.…”

Section: The Finder Algorithmmentioning

confidence: 99%

How Often Can Earthquake Early Warning Systems Alert Sites With High‐Intensity Ground Motion?

et al. 2020

View full text Add to dashboard Cite

Although numerous Earthquake Early Warning (EEW) algorithms have been developed to date, we lack a detailed understanding of how often and under what circumstances useful ground motion alerts can be provided to end users. In particular, it is unclear how often EEW systems can successfully alert sites with high ground motion intensities. These are the sites that arguably need EEW alerts the most, but they are also the most challenging ones to alert because they tend to be located close to the epicenter where the seismic waves arrive first. Here we analyze the alerting performance of the Propagation of Local Undamped Motion (PLUM), Earthquake Point‐Source Integrated Code (EPIC), and Finite‐Fault Rupture Detector (FinDer) algorithms by running them retrospectively on the seismic strong‐motion data of the 219 earthquakes in Japan since 1996 that exceeded Modified Mercalli Intensity (MMI) of 4.5 on at least 10 sites (Mw 4.5–9.1). Our analysis suggests that, irrespective of the algorithm, EEW end users should expect that EEW can often but not always provide useful alerts. Using a conservative warning time (tw) definition, we find that 40–60% of sites with strong to extreme shaking levels receive alerts with tw > 5 s. If high‐intensity shaking is caused by shallow crustal events, around 50% of sites with strong (MMI~6) and <20% of sites with severe and violent (MMI ≥ 8) shaking receive alerts with tw > 5 s. Our results provide detailed quantitative insight into the expected alerting performance for EEW algorithms under realistic conditions. We also discuss how operational systems can achieve longer warning times with more precautionary alerting strategies.

show abstract

“…Geodetic systems, however, successfully characterized the El Mayor‐Cucapah event using a similar (United States‐only) network geometry (Allen & Ziv, 2011; Grapenthin et al, 2014a; Ruhl et al, 2017) and have been shown to contribute to alarms in sparse seismic networks through S wave detections (Grapenthin et al, 2017). With the addition of near‐source stations, seismic‐finite‐source algorithms like FinDer are better able to model the 2010 M w 7.2 El Mayor earthquake (Böse et al, 2015). Using asymmetrical GM templates, FinDer is also now able to model offshore subduction zone events.…”

Section: Introductionmentioning

confidence: 99%

Quantifying the Value of Real‐Time Geodetic Constraints for Earthquake Early Warning Using a Global Seismic and Geodetic Data Set

et al. 2019

View full text Add to dashboard Cite

Geodetic earthquake early warning (EEW) algorithms complement point-source seismic systems by estimating fault-finiteness and unsaturated moment magnitude for the largest, most damaging earthquakes. Because such earthquakes are rare, it has been difficult to demonstrate that geodetic warnings improve ground motion estimation significantly. Here, we quantify and compare timeliness and accuracy of magnitude and ground motion estimates in simulated real time from seismic and geodetic observations for a suite of globally distributed, large earthquakes. Magnitude solutions saturate for the seismic EEW algorithm (we use ElarmS) while the ElarmS-triggered Geodetic Alarm System (G-larmS) reduces the error even for its first solutions. Shaking intensity (Modified Mercalli Intensity, MMI) time series calculated for each station and each event are assessed based on MMI threshold crossings, allowing us to accurately characterize warning times per station. We classify alerts and find that MMI 4 thresholds result in true positive alerts for only 13.7% of sites exceeding MMI 4 with a median warning time of 18.9 s for ElarmS, while G-larmS issues true positive alerts for 52.3% of all sites exceeding MMI 4 with a significantly longer median warning time of 55.8 s. The geodetic EEW system reduces the number of missed alerts for a threshold of MMI 4 from 48.7% to 19.2% for all sites, but also increases the number of false positive alerts from 1.2% to 13.4% of all sites. By quantifying increased accuracy in magnitude, ground motion estimation, and alert timeliness, we demonstrate that finite-fault geodetic algorithms add significant value, including better cost savings performance, to point-source seismic EEW systems for large earthquakes.

show abstract

Finite-Fault Rupture Detector (FinDer): Going Real-Time in CalifornianShakeAlertWarning System

Cited by 55 publications

References 42 publications

Location of largest earthquake slip and fast rupture controlled by along‐strike change in fault structural maturity due to fault growth

Location of largest earthquake slip and fast rupture controlled by along‐strike change in fault structural maturity due to fault growth

How Often Can Earthquake Early Warning Systems Alert Sites With High‐Intensity Ground Motion?

Quantifying the Value of Real‐Time Geodetic Constraints for Earthquake Early Warning Using a Global Seismic and Geodetic Data Set

Contact Info

Product

Resources

About