Real-time earthquake monitoring: Early warning and rapid response

A panel was established to investigate the subject of real-time earthquake monitoring (RTEM) and suggest recommendations on the feasibility of using a real-time earthquake warning system to mitigate earthquake damage in regions of the United States. The findings of the investigation and the related recommendations are described in this report. A brief review of existing real-time seismic systems is presented with particular emphasis given to the current California seismic networks. Specific applications of a real-time monitoring system are discussed along with issues related to system deployment and technical feasibility. In addition, several non-technical considerations are addressed including cost-benefit analysis, public perceptions, safety, and liability

Bridges Structural Health Monitoring and Deterioration Detection Synthesis of Knowledge and Technology

INE/AUTC 10.0

UK earthquake monitoring 2002/2003

The aims of the Seismic Monitoring and Information Service are to develop and maintain a national database of seismic activity in the UK for use in seismic hazard assessment, and to provide near-immediate responses to the occurrence, or reported occurrence, of significant events. The British Geological Survey (BGS) has been charged with the task of operating and further developing a uniform network of seismograph stations throughout the UK in order to acquire standardised data on a long-term basis. The project is supported by a group of organisations under the chairmanship of the Office of the Deputy Prime Minister (ODPM) with major financial input from the Natural Environment Research Council (NERC). This Customer Group is listed in Annex A. In the 14th year of the project (April 2002 to March 2003), three subnetworks were upgraded with the installation of data loggers running under the QNX operating system, and a strong motion instrument was installed at Hartland in North Devon. The increasing number of acceleration records being captured by strong motion instruments, is feeding into a better understanding of attenuation and seismic hazard in the UK. Some 235 earthquakes were located by the monitoring network in 2002, with 87 of them having magnitudes of 2.0 ML or greater (Annex B). A total of 42 events in this magnitude category were reported as felt along with 6 smaller ones. Nine strong-motion records were captured from six of the nineteen sites now equipped with strong motion instruments. The largest earthquake in the reporting year, with a magnitude of 4.7 ML, occurred near Dudley on 22 September. It was felt up to 337 km away and over an area of 126,000 km2 (Isoseismal 3 EMS) and reached a maximum intensity of 5 on the European Macroseismic Scale (EMS, Annex H). A peak ground acceleration of 153 mms -2 was recorded on the three-component accelerometer at Keyworth, a distance of 83 km from the epicentre. The focal mechanism indicates strike slip movement along near vertical fault planes striking either NNE-SSW or WNW-ESE. The following month, an earthquake sequence commenced near Manchester with 117 events located, 37 of which were felt by the local population. The sequence caused widespread alarm in the greater Manchester area. The largest offshore earthquake occurred in the central North Sea on 12 October 2002 with a magnitude of 3.5 ML, approximately 70 km east of the Shetland Islands. In addition to earthquakes, BGS frequently receives reports of seismic events felt and heard, which on investigation prove to be sonic booms, spurious or in coalfield areas, where much of the activity is probably induced by mining. During the reporting period, data from six sonic events were processed and reported upon following public concern or media attention. All significant felt events and some others were reported rapidly to the Customer Group through seismic alerts sent by e-mail. The alerts were also published on the Internet (http://www.earthquakes.bgs.ac.uk). Monthly seismic bulletins were issued six weeks in arrears and, following revision, were compiled into an annual bulletin (Simpson, 2003). In all these reporting areas, scheduled targets have been met or surpassed. Maintenance and protection of historical archives, another primary goal of the project, has continued and has been enhanced by donations of the Soil Mechanics UK data, from a study in the early 1980’s and the British Association for the Advancement of Science Seismological Committee archives. The environmental monitoring stations at Eskdalemuir and Hartland observatories recorded a variety of parameters throughout the year and the data are now accessible on-line through an Internet connection

Bayesian inference of focal mechanisms and backprojection methods for source kinematics characterization

The general goal of this thesis has been to characterize the seismic source of an earthquake. A source can be characterized by macroscopic characteristics in the approximation of a point source, as the location of the hypocenter, moment magnitude of the event and the focal mechanism. Moreover, we can also provide characteristics of the extended source, as its spatial dimensions or the final slip map on the fault plane rather than an average value. Another punctual quantity that can be provided is rupture velocity. We have focused not only on the moderate-to-large events, but we have also tried to infer characteristics for micro-seismicity, believing that the latter is a key to understanding more large-scale mechanisms (De Matteis, 2012). In particular, we focused on the estimation of focal mechanism of microearthquakes (Mw< 3). Firstly, we have developed an algorithm in an evolutionary Bayesian framework to give a rapid estimation of the earthquake focal mechanism using the few seconds of P-wave since the origin time of a set of recording stations for moderate earthquakes (Mw 4.5 to 6.5). Then, opportunely modifying this procedure allowing for the inclusion of S/P amplitude and inclusion of polarity, we tried to infer the focal mechanism also of micro-earthquakes (local magnitude < Ml 3.0). We then investigated two different approaches for back-projection. We performed the back projection as in Marcklin et al,2012 but near source and applied to a moderate event, the 6.5 Mw 2016 Norcia earthquake, retrieving the dominant rupture propagation toward south. Moreover, the duration (~8s) is in agreement with references. This approach beamforms and stacks displacement amplitude directly on the fault plane to retrieve slip rate and slip on the plane. There is also a different strategy to perform the back-projection (Xie & Meng, 2020) which locates the seismic radiators, that are sub-events of an earthquake. We applied the Multi-array Back-projection to study 3 different earthquakes at local and regional scales, in different tectonic regimes, to determine the location of seismic radiators and we used the distance from seismic radiators as source-to-site distance metric to considering for the path effect in local Ground Motion Prediction Equations. This technique does not require the discretization of the source in sub-sources, neither to orient the fault plane in the space. It works to match the coherency of waveforms to locate seismic radiators, which distribution reflects the main direction of the rupture and also the rupture length. We used the distance of stations to radiators at local scale in an evolutionary approach to obtain estimation of Peak Ground Acceleration (PGA) in time, predicting in good agreement the observed PGA some seconds before

Seismological data acquisition and signal processing using wavelets

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This work deals with two main fields: a) The design, built, installation, test, evaluation, deployment and maintenance of Seismological Network of Crete (SNC) of the Laboratory of Geophysics and Seismology (LGS) at Technological Educational Institute (TEI) at Chania. b) The use of Wavelet Transform (WT) in several applications during the operation of the aforementioned network. SNC began its operation in 2003. It is designed and built in order to provide denser network coverage, real time data transmission to CRC, real time telemetry, use of wired ADSL lines and dedicated private satellite links, real time data processing and estimation of source parameters as well as rapid dissemination of results. All the above are implemented using commercial hardware and software which is modified and where is necessary, author designs and deploy additional software modules. Up to now (July 2008) SNC has recorded 5500 identified events (around 970 more than those reported by national bulletin the same period) and its seismic catalogue is complete for magnitudes over 3.2, instead national catalogue which was complete for magnitudes over 3.7 before the operation of SNC. During its operation, several applications at SNC used WT as a signal processing tool. These applications benefited from the adaptation of WT to non-stationary signals such as the seismic signals. These applications are: HVSR method. WT used to reveal undetectable non-stationarities in order to eliminate errors in site’s fundamental frequency estimation. Denoising. Several wavelet denoising schemes compared with the widely used in seismology band-pass filtering in order to prove the superiority of wavelet denoising and to choose the most appropriate scheme for different signal to noise ratios of seismograms. EEWS. WT used for producing magnitude prediction equations and epicentral estimations from the first 5 secs of P wave arrival. As an alternative analysis tool for detection of significant indicators in temporal patterns of seismicity. Multiresolution wavelet analysis of seismicity used to estimate (in a several years time period) the time where the maximum emitted earthquake energy was observed

Project OASIS: The Design of a Signal Detector for the Search for Extraterrestrial Intelligence

An 8 million channel spectrum analyzer (MCSA) was designed the meet to meet the needs of a SETI program. The MCSA puts out a very large data base at very high rates. The development of a device which follows the MCSA, is presented

Ensuring the resilience of wireless sensor networks to malicious data injections through measurements inspection

Malicious data injections pose a severe threat to the systems based on \emph{Wireless Sensor Networks} (WSNs) since they give the attacker control over the measurements, and on the system's status and response in turn. Malicious measurements are particularly threatening when used to spoof or mask events of interest, thus eliciting or preventing desirable responses. Spoofing and masking attacks are particularly difficult to detect since they depict plausible behaviours, especially if multiple sensors have been compromised and \emph{collude} to inject a coherent set of malicious measurements. Previous work has tackled the problem through \emph{measurements inspection}, which analyses the inter-measurements correlations induced by the physical phenomena. However, these techniques consider simplistic attacks and are not robust to collusion. Moreover, they assume highly predictable patterns in the measurements distribution, which are invalidated by the unpredictability of events. We design a set of techniques that effectively \emph{detect} malicious data injections in the presence of sophisticated collusion strategies, when one or more events manifest. Moreover, we build a methodology to \emph{characterise} the likely compromised sensors. We also design \emph{diagnosis} criteria that allow us to distinguish anomalies arising from malicious interference and faults. In contrast with previous work, we test the robustness of our methodology with automated and sophisticated attacks, where the attacker aims to evade detection. We conclude that our approach outperforms state-of-the-art approaches. Moreover, we estimate quantitatively the WSN degree of resilience and provide a methodology to give a WSN owner an assured degree of resilience by automatically designing the WSN deployment. To deal also with the extreme scenario where the attacker has compromised most of the WSN, we propose a combination with \emph{software attestation techniques}, which are more reliable when malicious data is originated by a compromised software, but also more expensive, and achieve an excellent trade-off between cost and resilience.Open Acces

The ‘Meanings’ and ‘Enactments’ of Science and Technology: ANT-Mobilities’ Analysis of Two Cases

In this work I study two cases involving practices of science and technology in the backdrop of related and recent curricular reforms in both settings. The first case study is based on the 2005 South Asian earthquake in Muzaffarabad, Pakistan which led to massive losses including large scale injuries and disabilities. This led to reforms at many levels ranging from disaster management to action plans on disability, including educational reforms in rehabilitation sciences. Local efforts to deal with this disaster led to innovative approaches such as the formation of a Community Based Rehabilitation (CBR) model by a local NGO, which I study in detail. The second case study is based on the recent reform of science and technology curriculum in Ontario, which is related to the release of the 2007 Intergovernmental Panel for Climate Change (IPCC) reports. With climate change science driving this reform with curricular demands for students to learn ‘what scientists do’, my second case study details the formation of the Canadian CloudSat CALIPSO Validation Project (C3VP) and scientific practices which depict cutting edge science related to climate change. Towards contending with the complexity inherent in these cases, I have developed a hybrid framework which is based on Actor-Network Theory (ANT) and the mobilities paradigm while drawing on some aspects of the Annales school of historians. The resulting historical sociology or historiography depicts how these various networks were formed via mobilities of various actor-networks and vice versa. The practices involved in both cases evolved over time and required innovation in times of crises and challenges, and are far more than simple applications of method as required by biomedical and positivist representations of science inherent in both educational reforms. Non-human agency in the form of crisis and disaster also emerges as a key reason for the formation of these networks. Drawing from both cases, I introduce the concept of “transectionalities” as a metaphor which represent configurations of actor-networks in science and technology geared towards dealing with crisis and disaster scenarios. Based on these findings, I also extend the idea of “multiple ontologies” by Mol (2002) to “Epistemic-Ontologic-Techne-” configurations which is sensitive to considerations of time. Moreover, I also find that mathematics is a key mobilizing actor and material semiotic which mediates communication between humans and non-humans and term these dynamics as “mathematical mobilities.” Based on case study one, I also suggest the notion of “affective care” in clinical reasoning, which is based on enhancing the beneficial effect of human to human relationships in these engagements