A low-cost, ANSS class B, networked Accelerometer for Earthquake Early Warning

Motivation

A 2013 study commissioned by the Insurance Bureau of Canada [1] suggests that an earthquake causing significant damage may occur with a chance of roughly 30 % within the next 50 years. Current efforts in the Province of British Columbia focus on the early detection of Cascadia subduction events with a small number of high sensitivity strong motion seismometers and GNSS instruments at relative large inter-station distances. This network could be supplemented with less sensitive accelerometers to increase station density in particular in urban areas and to address crustal earthquakes which can occur anywhere in south-western BC and Haida Gwaii.
Any low-cost instrument in this network should not transmit full waveform data to a central facility for processing and analysis but should compute relevant parameters on-line, on-site and in real time by means of an integrated (embedded) computer system. Only EEW relevant parameters are transmitted to a warning centre. This will reduce system latencies substantially.
We have built a prototype of a low-cost strong motion seismometer and have implemented capabilities from established methods and technologies, focused on what has been achieved in California and the European Union Framework Program projects "SAFER" and "REAKT". We use a software architecture where future extensions are possible.

Objectives


Versatile: 3-axis accelerometer, digitizer, recorder in one package

Small: Form-factor suitable for a pressure-case or post-hole enclosure

Low power: Long operation on UPS in case of line-power loss

Sensitive: Self noise ≈ 50μg RMS in 50 Hz

Smart: On board real-time EEW signal processing

Networked: Internet telemetry, NTP/PTP time synchronization

Fast: Direct, real-time reporting of EEW relevant events and parameters

Options: Relay output for On-Site warning [Zollo et al., 2010]

Full backward compatibility: Will fit seamlessly into existing MoT-I/GSC BCSIMS S/M network.

Specifications of a Prototype/Proof-of-Concept and First Test Results

SeismoPI-3-small.jpg Figure 1: Computer and Accelerograph in one small package

SP_Proc.png

Figure 2: Schematic embedded system, real-time signal processing. Yellow labels mark backward compatibility units, red labels mark EEW specific signal processing [8],[9],[11],[6],[5]. A general purpose input/output (GPIO) can steer a relay. On-site alert levels for Pd and τp are from [11]

Here are Testdata and data recorded during a real earthquake


References

[1]
AIR-Worldwide. Study of impact and the insurance and economic cost of a major earthquake in British Columbia and Ontario/Québec, October 2013. Commissioned by the Insurance Bureau of Canada.
[2]
R. M. Allen and H. Kanamori. The Potential For Earthquake Early Warning in Southern California. Science, 300 (5620): 786-789, 5 2003.
[3]
H. M. Brown, R. M. Allen, M. Hellweg, O. Khainovski, and D. Neuhauser. Development of the ELarmS methodology for earthquake early warning: Realtime application in California and offline testing in Japan. Soil Dyn Earthquake Eng, 31: 188-200, 2011. doi: 10.1016/j.soildyn.2010.03.008.
[4]
H. Kao, C.-W. Kan, R.-Y. Chen, C.-H. Chang, A. Rosenberger, T.-C. Shin, P.-L. Leu, K.-W. Kuo, and W.-T. Liang. Locating, monitoring, and characterizing typhoon-linduced landslides with real-time seismic signals. Landslides, 9 (4): 557-563, 2012. ISSN 1612-510X. doi: 10.1007/s10346-012-0322-z.
[5]
I. Kurzon, F. Vernon, A. Rosenberger, and Y. Ben-Zion. Real-time automatic detectors of P and S waves using Singular Value Decomposition. BSSA, 104 (4): 1696-1708, 2014. doi: 10.1785/0120130295.
[6]
H. Kuyuk and R. Allen. A global approach to provide magnitude estimates for earthquake early warning alerts. Geophys. Res. Lett., 40 (24): 6329–6333, 2013. doi: 10.1002/2013GL058580.
[7]
Y.-C. Liao, H. Kao, A. Rosenberger, and S.-K. Hsu. Delineating complex spatiotemporal distribution of earthquake aftershocks: An improved source-scanning algorithm. Geophys. J. Int., 189: 1753-1770, 2012. doi: 10.1111/j.1365-246X.2012.05457.x.
[8]
A. B. Lockman and R. M. Allen. Magnitude-period scaling relations for japan and the pacific northwest: Implications for Earthquake Early Warning. BSSA, 97 (1B): 140-150, 2007. doi: 10.1785/0120040091.
[9]
A. Rosenberger. Realtime Ground-Motion Analysis: Distinguishing P and S Arrivals in a Noisy Environment. Bull. Seism. Soc. Am., 100 (3): 1252-1262, 2010. doi: 10.1785/0120090265.
[10]
G. Wurman, R. M. Allen, and P. Lombard. Toward earthquake early warning in northern California. J. Geophys. Res., 112, 2007. doi: 10.1029/2006JB004830.
[11]
A. Zollo, O. Amoroso, M. Lancieri, Y.-M. Wu, and H. Kanamori. A threshold-based earthquake early warning using dense accelerometer networks. Geophys. J. Int., 183: 963-974, 2010. doi: 10.1111/j.1365-246X.2010.04765.x.



March 2017