Earthquake Early Warning System (EEWs) for the New Madrid Seismic Zone

Part 1: Research in the last decade on Earthquake Early Warning Systems (EEWSs) has undergone rapid development in terms of theoretical and methodological advances in real time data analysis, improved telemetry, and computer technology and is becoming a useful tool for practical real time seismic hazard mitigation. The main focus of this study is to undertake a feasibility study of an EEWS for the New Madrid Seismic Zone (NMSZ) from the standpoint of source location. Magnitude determination is addressed in a separate paper. The NMSZ covers a wide area with several heavily populated cities, vital infrastructures, and facilities located within a radius of less than 70 km from the epicenters of the 1811-1812 earthquakes. One of the challenges associated with the NMSZ is that while low to moderate levels of seismic activity are common, larger earthquakes are rare (i.e. there are no instrumentally recorded data for earthquakes with magnitudes greater than M5.5 in the NMSZ). We also recognize that it may not be realistic to provide early warning for all possible sources as is done on the west coast U.S. and we therefore focus on a specific source zone. We examine the stations within the NMSZ in order to answer the question What changes should be applied to the NMSZ network to make it suitable for earthquake early warning (EEW). We also explore needed changes to the Advanced National Seismic System (ANSS) Earthquake Monitoring System Real Time (AQMS RT) data acquisition system to make it useful for EEW. Our results show that EEW is feasible, though several technical challenges remain in incorporating its use with the present network.Part 2: Increasing vulnerability of metropolitan areas within stable continental regions (SCR), such as Memphis, TN and St. Louis, MO near the New Madrid Seismic Zone (NMSZ), to earthquakes and the very low probability level at which short term earthquake forecasting is possible make an earthquake early warning system (EEWS) a viable alternative for effective real-time risk reduction in these cities. In this study, we explore practical approaches to earthquake early warning (EEWS), and test the adaptability and potential of the real-time monitoring system in the NMSZ. We determine empirical relations based on amplitude and frequency magnitude proxies from the initial four seconds of the P-waveform records available from the Cooperative New Madrid Seismic Network (CNMSN) database for magnitude ????\u3e2.1. The amplitude-based proxies include low pass filtered peak displacement (Pd), peak velocity (Pv), and integral of the velocity squared (IV2), whereas the frequency-based proxies include predominant period (????????), characteristic period (????????), and log average period (????????????????). Very few studies have considered areas with lower magnitude events. With an active EEW system in the NMSZ, damage resulting from the catastrophic event, as witnessed in 1811-1812, may be mitigated in real-time

Model Bias Analysis Using Statistical Methods with the NGA East Ground Motion Database

The Next Generation Attenuation (NGA) East project has an updated database for Central and Eastern North America (CENA) ground motions. I analyzed the performance of ground motion prediction equations (GMPEs) used in the United States Geological Survey (USGS) National Seismic Hazard Mapping Project (NSHMP) and other potential GMPEs used in the CENA through bias analysis, model inadequacies check using statistical tests and finally ranking the GMPEs using log likelihood (LLH), and the Euclidean Distance Based Ranking (EDR) technique. From bias analysis, Atkinson and Boore (2011) (model A08p), Atkinson and Boore (2011) (model AB06p), and Atkinson and Boore (2006) (model AB06+) with 200 bar stress drop performed better than other GMPEs. EDR results show models A08, AB06p, and AB06+ as the best performing models for combined site classes. Models AB06p, EPRI (2004) cluster2 model (EPRI2), AB06+ and Silva et al. (2002) (SD02) matched the data well in rock sites

Improved CENA regression relationships between modified mercalli intensities and ground-motion parameters

Comparisons between peak ground motions (PGMs) and intensities are mainly based on the regression of felt intensity with peak ground acceleration (PGA), peak ground velocity (PGV), response spectral values, and occasionally with maximum displacement. Using the Next Generation Attenuation-East database, we update and extend the relations of Dangkua and Cramer (2011). We start by developing magnitude and distance-independent linear regression relationships between modified Mercalli intensity (MMI) in the range of I ≤ MMI ≤ VII and the ground-motion parameters (GMPs) of PGA, PGV, and 21 pseudospectral accelerations for central and eastern North America (CENA).We correct for recently acknowledged differences between community Internet intensities (CIIs) and MMI (Hough, 2013, 2014; Boyd and Cramer, 2014; Tosi et al., 2015). We then perform residual analysis to evaluate whether there are any discrepancies and dependency, first with magnitude and then distance. For the magnitude-dependent analysis, we use a bilinear fit. This bilinear magnitude dependence is especially important for longer periods. The residuals show homoskedasticity with zero mean and are serially correlated. We correct for the serial correlation using the Cochrane–Orcutt procedure. Our new ground-motion intensity correlation equations for CENA have the form log10(Y) = c1 + c2 × I + c3× min{Mw;Mt} + c4 × log10(Dist), in which log10(Y) is the GMP, Mw is the moment magnitude, Mt is the magnitude of the bend in the bilinear magnitude dependence, log10(Dist) is the distance term, I is the intensity of interest (MMI or CII), and c1, c2, c3, and c4 are the coefficients of regression. The equation is invertible for obtaining both CII and MMI from the PGM of interest and vice versa

Earthquake early warning feasibility study for the new Madrid seismic zone

In the last decade, research on earthquake early warning systems (EEWSs) has undergone rapid development in terms of theoretical and methodological advances. These include advances in real-time data analysis, improved telemetry, and computer technology; they are becoming useful tools for practical real-time seismic hazard mitigation. The main focus of this project is to undertake a feasibility study of an EEWS for the New Madrid seismic zone (NMSZ) from the standpoint of source location. Magnitude determination is addressed in a separate paper. The NMSZ covers a wide area with several heavily populated cities, vital infrastructures, and facilities located within a radius of less than 70 km from the epicenters of the 1811-1812 earthquakes. One of the challenges associated with the NMSZ is that whereas low-to-moderate levels of seismic activity are common, larger earthquakes are rare (i.e., there are no instrumentally recorded data for earthquakes with magnitudes greater than M 5.5 in the NMSZ). We also recognize that it may not be realistic to provide early warnings for all possible sources, as is done on the west coast of the United States; as such, we focus on a specific source zone. We examine the stations within the NMSZ to answer the following question: “What changes should be applied to the NMSZ network to make it suitable for EEW?” We also explore needed changes to the Advanced National Seismic System (ANSS) earthquake monitoring system real time (AQMS RT) data acquisition system (DAS) to make it useful for EEW. Our results show that EEW is feasible, though several technical challenges remain in incorporating its use with the present network