scholarly journals Application of an Objective Detection Method of Long-Term Slow Slip Events using GNSS Data: Detection of Short-Term Slow Slip Events and Estimation of Moment Magnitude of Long-Term Slow Slip Events

2021 ◽  
Vol 69 (0) ◽  
pp. 1-14
Author(s):  
Akio KOBAYASHI
Keyword(s):  
Detection Method ◽  
Moment Magnitude ◽  
Data Detection ◽  
Slow Slip ◽  
Short Term ◽  
Slow Slip Events ◽  
Objective Detection ◽  
Gnss Data

scholarly journals Spatiotemporal slip distributions associated with the 2018–2019 Bungo Channel long-term slow slip event inverted from GNSS data

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Yukinari Seshimo ◽  
Shoichi Yoshioka
Keyword(s):  
Time Series Data ◽  
Series Data ◽  
Slow Slip ◽  
Slow Slip Events ◽  
Bungo Channel ◽  
Slip Event ◽  
The Moment ◽  
Gnss Data ◽  
Gnss Time Series

AbstractLong-term slow slip events (L-SSEs) have repeatedly occurred beneath the Bungo Channel in southwestern Japan with durations of several months to a couple of years, with a recurrence interval of approximately 6 years. We estimated the spatiotemporal slip distributions of the 2018–2019 Bungo Channel L-SSE by inverting processed GNSS time series data. This event was divided into two subevents, with the first on the southwest side of the Bungo Channel from 2018.3 to 2018.7 and the second beneath the Bungo Channel from 2018.8 to 2019.4. Tectonic tremors became active on the downdip side of the L-SSE occurrence region when large slow slips took place beneath the Bungo Channel. Compared with the previous Bungo Channel L-SSEs, this spatiotemporal slip pattern and amount were similar to those of the 2002–2004 L-SSE. However, the slip expanded in the northeast and southwest directions in the latter half of the second subevent. The maximum amount of slip, the maximum slip velocity, the total released seismic moment, and the moment magnitude of the 2018–2019 L-SSE were estimated to be 28 cm, 54 cm/year, $$4.4 \times 10^{19}$$ 4.4 × 10 19 Nm, and 7.0, respectively, all of which were the largest among the 1996–1998, 2002–2004, 2009–2011, and 2018–2019 L-SSEs.

Detection of short-term slow slip events along the Nankai Trough, southwest Japan, using GNSS data

2013 ◽  
Vol 118 (6) ◽  
pp. 3112-3125 ◽  
Author(s):  
Takuya Nishimura ◽  
Takanori Matsuzawa ◽  
Kazushige Obara
Keyword(s):  
Nankai Trough ◽  
Slow Slip ◽  
Southwest Japan ◽  
Short Term ◽  
Slow Slip Events ◽  
Gnss Data

Estimation of frictional properties and slip evolution on a long-term slow slip event fault with the ensemble Kalman filter: numerical experiments

2019 ◽  
Vol 219 (3) ◽  
pp. 2074-2096 ◽  
Author(s):  
Kazuro Hirahara ◽  
Kento Nishikiori
Keyword(s):  
Surface Displacement ◽  
Slip Rate ◽  
Slow Slip ◽  
Slow Slip Events ◽  
Actual Distribution ◽  
Frictional Properties ◽  
Data Analyses ◽  
Bungo Channel ◽  
Megathrust Faults ◽  
Gnss Data

Summary A variety of slow slip events at subduction zones have been observed. They can be stress meters for monitoring the stress state of megathrust faults during their earthquake cycles. In this study, we focus on long-term slow slip events (LSSEs) recurring at downdip portions of megathrust faults among such slow earthquakes. Data analyses and simulation studies of LSSEs have so far been executed independently. In atmosphere and ocean sciences, data assimilations that optimally combine data analyses and simulation studies have been developed. We develop a method for estimating frictional properties and monitoring slip evolution on an LSSE fault, with a sequential data assimilation method, the ensemble Kalman filter (EnKF). We executed numerical twin experiments for the Bungo Channel LSSE fault in southwest Japan to validate the method. First, based on a rate- and state-dependent friction law, we set a rate-weakening circular LSSE patch on the rate-strengthening flat plate interface, whose critical nucleation size is larger than that of the patch, and reproduced the observed Bungo Channel LSSEs with recurrence times of approximately 7 yr and slip durations of 1 yr. Then, we synthesized the observed data of surface displacement rates at uniformly distributed stations with noises from the simulated slip model. Using our EnKF method, we successfully estimated the frictional parameters and the slip rate evolution after a few cycles. Secondly, we considered the effect of the megathrust fault existing in the updip portion of the LSSE fault, as revealed by kinematic inversion studies of Global Navigation Satellite System (GNSS) data and added this locked region with a slip deficit rate in the model. We estimated the slip rate on the locked region only kinematically, but the quasi-dynamic equation of motion in each LSSE fault cell includes the stress term arising from the locked region. Based on this model, we synthesized the observed surface displacement rate data for the actual distribution of GNSS stations and executed EnKF estimations including the slip rate on the locked region. The slip rate on the locked region could be quickly retrieved. Even for the actual distribution of GNSS stations, we could successfully estimate frictional parameters and slip evolution on the LSSE fault. Thus, our twin numerical experiments showed the validity of our EnKF method, although we need further studies for actual GNSS data analyses.

scholarly journals An Attempt at Simulation of Long Term Slow Slip Events and Seismic Cycle in the Tokai Region

2009 ◽  
Vol 62 (2/3) ◽  
pp. 67-84 ◽  
Author(s):  
Fuyuki HIROSE ◽  
Kenji MAEDA ◽  
Hiroyuki TAKAYAMA
Keyword(s):  
Seismic Cycle ◽  
Slow Slip ◽  
Slow Slip Events ◽  
Tokai Region

scholarly journals Detection of short-term slow slip events along the Nankai Trough via groundwater observations

2013 ◽  
Vol 40 (23) ◽  
pp. 6079-6083
Author(s):  
Yuichi Kitagawa ◽  
Naoji Koizumi
Keyword(s):  
Nankai Trough ◽  
Slow Slip ◽  
Short Term ◽  
Slow Slip Events

scholarly journals Modeling the activity of short-term slow slip events along deep subduction interfaces beneath Shikoku, southwest Japan

2010 ◽  
Vol 115 ◽  
Author(s):  
Bunichiro Shibazaki ◽  
Shuhui Bu ◽  
Takanori Matsuzawa ◽  
Hitoshi Hirose
Keyword(s):  
Slow Slip ◽  
Southwest Japan ◽  
Short Term ◽  
Slow Slip Events
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