An effective method for small event detection: match and locate (M&amp;L)

Zhang, Miao; Wen, Lianxing

doi:10.1093/gji/ggu466

Cited by 116 publications

(68 citation statements)

References 47 publications

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“…The complexity in activation of aftershocks could be due to the fact that we simply assign the template location to the best detected event, and a better way to examine the spatiotemporal evolution may be to perform relocations for all the newly detected events. This would require additional measurements of differential travel times between tens of thousands of template and newly detected events [e.g., Shelly et al ., ; Zhang and Wen , ]. Alternatively, this could be a function of the relative roughness of the plate boundary.…”

Section: Discussionmentioning

confidence: 99%

Detailed spatiotemporal evolution of microseismicity and repeating earthquakes following the 2012 M_w 7.6 Nicoya earthquake

et al. 2017

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We apply a waveform matching technique to obtain a detailed earthquake catalog around the rupture zone of the 5 September 2012 moment magnitude 7.6 Nicoya earthquake, with emphasis on its aftershock sequence. Starting from a preliminary catalog, we relocate ~7900 events using TomoDD to better quantify their spatiotemporal behavior. Relocated aftershocks are mostly clustered in two groups. The first is immediately above the major coseismic slip patch, partially overlapping with shallow afterslip. The second one is 50 km SE to the main shock nucleation point and near the terminus of coseismic rupture, in a zone that exhibited little resolvable afterslip. Using the relocated events as templates, we scan through the continuous recording from 29 June 2012 to 30 December 2012, detecting approximately 17 times more than template events. We find 190 aftershocks in the first half hour following the main shock, mostly along the plate interface. Later events become more scattered in location, showing moderate expansion in both along‐trench and downdip directions. From the detected catalog we identify 53 repeating aftershock clusters with mean cross‐correlation values larger than 0.9, and indistinguishably intracluster event locations, suggesting slip on the same fault patch. Most repeating clusters occurred within the first major aftershock group. Very few repeating clusters were found in the aftershock grouping along the southern edge of the Peninsula, which is not associated with substantial afterslip. Our observations suggest that loading from nearby afterslip along the plate interface drives spatiotemporal evolution of aftershocks just above the main shock rupture patch, while aftershocks in the SE group are to the SE of the observed updip afterslip and poorly constrained.

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Section: Discussionmentioning

confidence: 99%

Detailed spatiotemporal evolution of microseismicity and repeating earthquakes following the 2012 M_w 7.6 Nicoya earthquake

et al. 2017

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“…Potential slave (detected) event locations are meshed in an area of 0.08°in latitude and 0.08°in longitude centered at each template event, with a searching interval of 0.0005°. Due to the strong trade-off between the depth and event 10.1029/2018JB015863 Journal of Geophysical Research: Solid Earth origin time for the station distribution we have, the depth of slave event cannot be well constrained (Billings et al, 1994;Zhang & Wen, 2015). So we fix the slave event depth to be that of the templates.…”

Section: Small Event Detection and Relocationmentioning

confidence: 99%

Seismicity Induced by Simultaneous Abrupt Changes of Injection Rate and Well Pressure in Hutubi Gas Field

et al. 2018

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Hutubi gas field, the largest gas storage field in China, has been operated on annual injection/extraction cycles since 9 June 2013. We study the seismicity near the gas field from 9 June 2013 to 22 October 2015, a time span that the gas field has experienced three injection periods and two extraction periods, and explore its physical mechanism based on the relationship between seismicity and field operation. We identify 273 events (ML > 1) in the region within 10 km of the gas field, with 97% of those occurring in the first two injection periods, 0.4% in the third injection period, and 1% in the two extraction periods. Seismicity in the first two injection periods occurs mostly as shallow clusters (focal depth < 2 km) at two locations: with one along the fault that marks the southern boundary of the gas field and the other about 2 km south to the southeastern tip of the gas field with the seismicity distributed along north‐south direction. The seismicity does not correlate with total gas injection volume, injection rate, or well pressure. It instead occurs 11–17 hr after simultaneous abrupt increases/decreases of gas injection rate and well pressure in the field operation in the first two injection periods when some accumulative injection has reached. Such relationship is consistent with a physical mechanism that the seismicity near Hutubi gas field is induced on pore‐pressured faults with a rate‐ and state‐dependent friction law through an abrupt change of stress in elastic and undrained poroelastic responses to simultaneous abrupt changes of injection rate and well pressure. Our study also points to the possibility that induced seismicity may be controllable in some practical field operations.

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“…The stringent condition of near co-location for this form of detector may be mitigated somewhat by using an empirical subspace detector (Barrett & Beroza 2014) or, for multiple stations, a region of possible source locations can be scanned for optimal network correlation (the so-called "Match and Locate" procedure: Zhang & Wen 2015). With sufficient waveform similarity, a direct scaling between aligned traces can result in a more accurate estimate of the relative magnitudes (and yields) of the events than a simple comparison of waveform amplitudes (e.g.…”

Section: Introductionmentioning

confidence: 99%

Accurate relative location estimates for the North Korean nuclear tests using empirical slowness corrections

Gibbons¹,

Pabian

Näsholm³

et al. 2016

Geophys. J. Int.

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SUMMARYDeclared North Korean nuclear tests in 2006, 2009, 2013, and 2016 were observed seismically at regional and teleseismic distances. Waveform similarity allows the events to be located relatively with far greater accuracy than the absolute locations can be determined from seismic data alone. There is now significant redundancy in the data given the large number of regional and teleseismic stations that have recorded multiple events, and relative location estimates can be confirmed independently by performing calculations on many mutually exclusive sets of measurements. Using a 1-dimensional global velocity model, the distances between the events estimated using teleseismic P phases are found to be approximately 25% shorter than the distances between events estimated using regional Pn phases. The 2009The , 2013, and 2016 events all take place within 1 km of each other and the discrepancy between the regional and teleseismic relative location estimates is no more than about 150 m. The discrepancy is much more significant when estimating the location of the more distant 2006 event relative to the later explosions with regional and teleseismic estimates varying by many hundreds of meters. The relative location of the 2006 event is challenging given the smaller number of observing stations, the lower signal-to-noise ratio, and significant waveform dissimilarity at some regional 2 S. J. Gibbons et al.stations. The 2006 event is however highly significant in constraining the absolute locations in the terrain at the Punggye-ri test-site in relation to observed surface infrastructure.For each seismic arrival used to estimate the relative locations, we define a slowness scaling factor which multiplies the gradient of seismic traveltime versus distance, evaluated at the source, relative to the applied 1-d velocity model. A procedure for estimating correction terms which reduce the double-difference time residual vector norms is presented together with a discussion of the associated uncertainty. The modified velocity gradients reduce the residuals, the relative location uncertainties, and the sensitivity to the combination of stations used. The traveltime gradients appear to be overestimated for the regional phases, and teleseismic relative location estimates are likely to be more accurate despite an apparent lower precision. Calibrations for regional phases are essential given that smaller magnitude events are likely not to be recorded teleseismically. We discuss

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An effective method for small event detection: match and locate (M&L)

Cited by 116 publications

References 47 publications

Detailed spatiotemporal evolution of microseismicity and repeating earthquakes following the 2012 M_w 7.6 Nicoya earthquake

Detailed spatiotemporal evolution of microseismicity and repeating earthquakes following the 2012 M_w 7.6 Nicoya earthquake

Seismicity Induced by Simultaneous Abrupt Changes of Injection Rate and Well Pressure in Hutubi Gas Field

Accurate relative location estimates for the North Korean nuclear tests using empirical slowness corrections

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An effective method for small event detection: match and locate (M&L)

Cited by 116 publications

References 47 publications

Detailed spatiotemporal evolution of microseismicity and repeating earthquakes following the 2012 Mw 7.6 Nicoya earthquake

Detailed spatiotemporal evolution of microseismicity and repeating earthquakes following the 2012 Mw 7.6 Nicoya earthquake

Seismicity Induced by Simultaneous Abrupt Changes of Injection Rate and Well Pressure in Hutubi Gas Field

Accurate relative location estimates for the North Korean nuclear tests using empirical slowness corrections

Contact Info

Product

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Detailed spatiotemporal evolution of microseismicity and repeating earthquakes following the 2012 M_w 7.6 Nicoya earthquake

Detailed spatiotemporal evolution of microseismicity and repeating earthquakes following the 2012 M_w 7.6 Nicoya earthquake