Application of high-rate GPS for earthquake rapid response and modelling: a case in the 2019 Mw 7.1 Ridgecrest earthquake

2020 ◽  
Vol 222 (3) ◽  
pp. 1923-1935
Author(s):  
Jin Fang ◽  
Caijun Xu ◽  
Jianfei Zang ◽  
Yangmao Wen ◽  
Chuang Song ◽  
...  
Keyword(s):  
Real Time ◽  
Moment Tensor ◽  
Propagation Speed ◽  
Source Model ◽  
High Rate ◽  
Centroid Moment Tensor ◽  
Magnitude Scaling ◽  
Global Positioning ◽  
Slip Event ◽  
Kaikoura Earthquake

SUMMARY The 2019 Mw 7.1 Ridgecrest earthquake opens an opportunity to investigate how soon we can produce a reliable fault geometry and subsequently a robust source model based on high-rate Global Positioning System (GPS) data. In this study, we conduct peak ground displacement (PGD) magnitude scaling, real-time centroid moment tensor (CMT) calculation and rapid kinematic slip inversion. We conclude that a four-station PGD warning with a magnitude of Mw 7.03 can be issued at 24 s after initiation of the rupture. Fast CMT inversion can initially recover the correct nodal planes at 30 s. The kinematic slip model reveals that the Mw 7.1 earthquake is a predominant dextral strike-slip event with both normal and thrust components resolved. The earthquake shows a bilateral rupture with a low propagation speed of ∼2.1 km s−1 and a slip maxima of ∼4 m. The total moment is 5.18 × 1019 N m (Mw 7.11). We further suggest that a reasonable source model will be available in a simulated real-time mode within 30 s after the earthquake occurring, without using full high-rate GPS waveforms. This research highlights the significance of high-rate GPS for rapid earthquake response and modelling of kinematic rupture, which is also generalized by the hypothetical real-time GPS analysis for the 2016 Mw 7.8 Kaikoura earthquake and the 2010 Mw 7.2 El Mayor-Cucapah earthquake.

Rapid Earthquake Source Description Using Variometric-Derived GPS Displacements toward Application to the 2019 Mw 7.1 Ridgecrest Earthquake

2021 ◽  
Author(s):  
Jianfei Zang ◽  
Caijun Xu ◽  
Yangmao Wen ◽  
Xiaohang Wang ◽  
Kefeng He
Keyword(s):  
Real Time ◽  
Early Warning ◽  
Moment Tensor ◽  
Continuous Phase ◽  
Earthquake Source ◽  
High Rate ◽  
Convergence Time ◽  
Centroid Moment Tensor ◽  
Origin Time ◽  
Broadcast Ephemeris

Abstract Using near-field high-rate Global Positioning System (GPS) displacements to invert for earthquake fault slips in real time has the potential to improve the accuracy of earthquake early warning or tsunami early warning. For such applications, real-time retrieval of high-accuracy GPS displacements is essential. Here, we report on rapid modeling of the 2019 Mw 7.1 Ridgecrest earthquake with real-time GPS displacements derived from a variometric approach with readily available broadcast ephemeris. This method calculates station variations in real time by differencing continuous phase observations and does not rely on precise orbit and clock information. The phase ambiguity is also removed, and thus the method does not suffer from a relatively long convergence time. To improve the accuracy of variometric displacements, we use a local spatial filter to decrease the influence of residual errors that cannot be removed completely by the time difference. We invert for the centroid moment tensor, static fault slips, and fault rupture process from the derived displacements. Our results show that all inverted models are available within about 65 s after the origin time of the earthquake and are comparable with models inverted by real-time precise point positioning displacements. This study highlights the great value of variometric displacements for the rapid earthquake source description with only broadcast ephemeris.

Comparison of local kinematic rupture joint inversion approaches for tsunami early warning: Examples of the 2017-2020 Mw > 6.3 East Aegean earthquakes

2021 ◽  
Author(s):  
Malte Metz ◽  
Marius Isken ◽  
Rongjiang Wang ◽  
Torsten Dahm ◽  
Haluk Özener ◽  
...  
Keyword(s):  
Early Warning ◽  
Joint Inversion ◽  
Moment Tensor ◽  
Strong Motion ◽  
Aegean Sea ◽  
High Rate ◽  
Source Inversion ◽  
Dynamic Rupture ◽  
Centroid Moment Tensor ◽  
Tsunami Early Warning

<p>The fast inversion of reliable centroid moment tensor and kinematic rupture parameters of earthquakes occurring near coastal margins is a key for the assessment of the tsunamigenic potential and early tsunami warning (TEW). In recent years, more and more multi-channel seismic and geodetic online station networks have been built-up to improve the TEW, for instance the GNSS and strong motion networks in Italy, Greece, and Turkey, additionally to the broadband seismological monitoring. Inclusion of such data for the fast kinematic source inversion can improve the resolution and robustness of its’ solutions. However, methods have to be further developed and tested to fully exploit the potential of such rich joint dataset.</p><p>In this frame, we compare and test two in-house developed, kinematic / dynamic rupture inversion methods which are based on completely different approaches. The IDS (Iterative Deconvolution and Stacking, Zhang et al., 2014) combines an iterative seismic network inversion with back projection techniques to retrieve subfault source time functions. The pseudo dynamic rupture model (Dahm et al., in review) links the rupture front propagation estimate based on the Eikonal equation with the dislocation derived from a boundary element method to model dislocation snapshots. We used the latter in both a fast rupture estimate and a fully probabilistic source inversion.</p><p>We use some Mw > 6.3 earthquakes that occurred in the coastal range of the Aegean Sea as an example for comparison: the Mw 6.3 Lesbos earthquake (12 June 2017), the Mw 6.6 Bodrum earthquake (20 July 2017), and the recent Mw 7.0 earthquake which occurred at Samos on 30 October 2020. The latter earthquake and the resulting tsunami caused fatalities and severe damage at the shorelines of Samos and around the city of Izmir, Turkey.<br>The fast estimates are based on only little data and/or prior information obtained from the regional seismicity catalogue and available active fault information. The large number of seismic (broadband, strong motion) and geodetic (high-rate GNSS) stations in local and regional distance from the earthquake with good azimuthal coverage jointly inverted with InSAR data allows for robust inversion results. These, and other solutions, are used as a reference for the comparison of our fast source estimates.<br>Preliminary results of the slip distribution and the source time function are in good agreement with modelling results from other authors.</p><p>We present our insights into the kinematics of the chosen earthquakes investigated by means of joint inversions. Finally, the accuracy of our first fast source estimates, which could be of potential use in tsunami early warning, will be discussed.</p>

scholarly journals Determining spatio-temporal characteristics of coseismic travelling ionospheric disturbances (CTID) in near real-time

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Boris Maletckii ◽  
Elvira Astafyeva
Keyword(s):  
Real Time ◽  
Tohoku Earthquake ◽  
Propagation Speed ◽  
High Rate ◽  
Ionospheric Disturbances ◽  
Temporal Characteristics ◽  
Travelling Ionospheric Disturbances ◽  
Spatio Temporal ◽  
Gnss Data ◽  
First Time

AbstractEarthquakes are known to generate ionospheric disturbances that are commonly referred to as co-seismic travelling ionospheric disturbances (CTID). In this work, for the first time, we present a novel method that enables to automatically detect CTID in ionospheric GNSS-data, and to determine their spatio-temporal characteristics (velocity and azimuth of propagation) in near-real time (NRT), i.e., less than 15 min after an earthquake. The obtained instantaneous velocities allow us to understand the evolution of CTID and to estimate the location of the CTID source in NRT. Furthermore, also for the first time, we developed a concept of real-time travel-time diagrams that aid to verify the correlation with the source and to estimate additionally the propagation speed of the observed CTID. We apply our methods to the Mw7.4 Sanriku earthquake of 09/03/2011 and the Mw9.0 Tohoku earthquake of 11/03/2011, and we make a NRT analysis of the dynamics of CTID driven by these seismic events. We show that the best results are achieved with high-rate 1 Hz data. While the first tests are made on CTID, our method is also applicable for detection and determining of spatio-temporal characteristics of other travelling ionospheric disturbances that often occur in the ionosphere driven by many geophysical phenomena.

The Homogenized Instrumental Seismic Catalog (HORUS) of Italy from 1960 to Present

2020 ◽  
Vol 91 (6) ◽  
pp. 3208-3222 ◽  
Author(s):  
Barbara Lolli ◽  
Daniele Randazzo ◽  
Gianfranco Vannucci ◽  
Paolo Gasperini
Keyword(s):  
Real Time ◽  
Moment Tensor ◽  
Regression Method ◽  
Online Resources ◽  
Time Interval ◽  
Empirical Relationships ◽  
Chi Square ◽  
Centroid Moment Tensor ◽  
Different Sources ◽  
Seismic Catalog

Abstract We implemented an automatic procedure to update in near-real time (daily to hourly) a homogeneous catalog of Italian instrumental seismicity to be used for forecasting experiments and other statistical analyses. The magnitudes of all events are homogeneously revalued to be consistent with Mw standard estimates made by the Global Centroid Moment Tensor project. For the time interval from 1960 to 15 April 2005, catalogs and online resources available for the Italian area were merged and all magnitudes were homogenized to Mw according to empirical relationships computed using the chi-square regression method, which properly consider the uncertainties of both variables. From 16 April 2005 to the present, an automatic procedure periodically downloads the data of the online bulletin of the Istituto Nazionale di Geofisica e Vulcanologia and of online moment tensor catalogs from respective websites, merges the different sources, and applies traditional magnitude conversions to Mw. The final catalog is provided on a website for public dissemination.

scholarly journals Centroid-moment tensor inversions using high-rate GPS waveforms

2012 ◽  
Vol 191 (1) ◽  
pp. 257-270 ◽  
Author(s):  
Thomas B. O’Toole ◽  
Andrew P. Valentine ◽  
John H. Woodhouse
Keyword(s):  
Moment Tensor ◽  
High Rate ◽  
Centroid Moment Tensor

New determinations of tides on the north-western Ross Ice Shelf

2020 ◽  
pp. 1-14
Author(s):  
Richard D. Ray ◽  
Kristine M. Larson ◽  
Bruce J. Haines
Keyword(s):  
Time Series ◽  
Tide Gauge ◽  
High Rate ◽  
Ice Shelf ◽  
Ross Ice Shelf ◽  
The North ◽  
Global Positioning ◽  
North Western

Abstract New determinations of ocean tides are extracted from high-rate Global Positioning System (GPS) solutions at nine stations sitting on the Ross Ice Shelf. Five are multi-year time series. Three older time series are only 2–3 weeks long. These are not ideal, but they are still useful because they provide the only in situ tide observations in that sector of the ice shelf. The long tide-gauge observations from Scott Base and Cape Roberts are also reanalysed. They allow determination of some previously neglected tidal phenomena in this region, such as third-degree tides, and they provide context for analysis of the shorter datasets. The semidiurnal tides are small at all sites, yet M2 undergoes a clear seasonal cycle, which was first noted by Sir George Darwin while studying measurements from the Discovery expedition. Darwin saw a much larger modulation than we observe, and we consider possible explanations - instrumental or climatic - for this difference.

Design of Urban Vehicle Dynamic and Real-Time Navigation System Based on WSNs, GPS, and GPRS Techniques

2013 ◽  
Vol 765-767 ◽  
pp. 3291-3294
Author(s):  
Cheng Lin Li ◽  
Zhi Yong Jiang
Keyword(s):  
Real Time ◽  
Global Positioning System ◽  
Navigation System ◽  
Traffic Congestion ◽  
Road Construction ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
General Packet Radio Service ◽  
Vehicle Navigation System ◽  
Global Positioning

Currently, the traffic congestion is a significant problem encountered in urban development, which should be resolved depending primarily on the management and deployment under the circumstance that road construction isn't able to keep the pace of automobile growth. WSNs (Wireless sensor networks), made up of numerous sensor nodes, form a multi-hop and self-organizing cellular system by wireless communication, which can realize real-time monitoring and collecting environmental information by cooperation. In this paper, a design of real-time and dynamic city vehicle navigation system is presented based on WSNs, GPS(Global Positioning System), and GPRS(General Packet Radio Service) techniques..

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