Work package number: WP9
Work package title: Early Warning and Development of the Real-time shake and loss information
WP Leader: KOERI
This WP has the objective of improving the existing earthquake early warning (EW) and rapid response (RR) systems in the Marmara Region (Istanbul) with the addition of a pilot landslide monitoring and EW system and introduction of new space technologies for monitoring and assessment of vulnerabilities.
The timeliness of our efforts to address seismic risk is testified by the appearance of a global, public-private partnership initiative such as the Global Earthquake Model (GEM), to establish uniform, open standards to calculate and communicate earthquake risk worldwide. MARsite will represent a key case study and may represent a GEM (Global earthquake Model) Regional Initiative, cross-fertilizing efforts in addressing geo-risk at both global and regional levels. Strong links -and thus effective coordination- between the MARsite consortium, GEO and GEM are ensured by the participation of a key research unit in Pavia, holding coordination of GEO Component C2 “Geohazards Monitoring, Alert, and Risk Assessment” of GEO task DI-01 “Informing Risk Management and Disaster Reduction”, and representing GEM within GEO as the GEM Alternate Principal.
Real-time actions focusing on decreasing the risks and improving search and rescue for the protection of the population has emerged as a viable way to support these preventive actions. Earthquake EW and RR methodologies are essentially based on the real-time capabilities of seismic monitoring systems to provide a reliable prediction of earthquake size and damaging effects based upon measurements of ground-motion parameters in narrow time windows. We aim to improve risk assessment by fusion of seismic risk factors on Istanbul with incorporation of new online data, techniques and methodologies (Task 1), integrate the landslide risk factor into risk assessment by development of a pilot landslide EW system (Task 2), develop the Shake and Loss information by fusion of hazard data: Improvement of the Istanbul Earthquake Rapid Response System with incorporation of new online data and incorporation of new methodologies (Task 3), and then finally merge earthquake and seismic vulnerability data, and other geospatial items relevant to spatially focused risk assessment: GEO Supersite showcase (Task 4). This WP will strongly benefit from the findings of previous FP6 projects NERIES, LESSLOSS, SERIES and SAFER and will be closely associated with the current EU FP7 projects NERA, SHARE, SYNER-G, REAKT and the OECD-initiated Global Earthquake Model program (GEM, www.globalquakemodel.org) to provide synergy and to avoid duplication.
Description of work
Task 1. Improvement of risk assessment in Istanbul with incorporation of new data, techniques and methodologies
Several studies have been conducted on the earthquake risk assessment in Istanbul (e.g. Strasser et al, 2008; Ansal et al., 2009; Erdik and Durukal, 2010; Erdik et al., 2010). These studies considered scenario based earthquake ground motion with no consideration of the intra-event variability of the ground motion. Yet, in addition to their intrinsic fragility relationships, the earthquake risk assessment of a megacity, such as Istanbul, with spatially distributed building portfolios and infrastructure systems requires quantification of the joint occurrence of ground-motion intensities at several sites, during the same earthquake (Jayaram and Baker, 2009).
In this task the current risk assessment (quantified in terms of building damage) will be improved by considering the intra-event variability of the ground motion. Geostatistical tools will be used to quantify the correlation between spatially distributed ground motion intensities based on the data obtained from the dense accelerometric network in Istanbul.
Task 2. Development of a pilot landslide EW system
This task aims to integrate the landslide risk factor into the risk assessment through development of a pilot landslide EW system
Landslides are one of the major causes of changes in landscape morphology for which reason the continuous monitoring of the latter must be considered as mandatory for landslide hazard and risk assessment (Ansal and Siyahi, 1994). Landslide monitoring and instrumentation can be performed at different levels and considering diverse set of parameters.
The monitoring system to measure the indicator parameters identified as signalling changes in stability. These may include:
- Meteorological monitoring – primarily rainfall, however also wind, pressure and temperature may also be measured and supplied to the weather prediction model as part of an iterative feedback for improving the short and long term forecasts.
- Geotechnical/geological/hydrological monitoring – may include point sensors such as pore pressure, slope rotation, tension crack extension or other measurements indicating the physical or morphological changes. More esoteric sensors may be considered as appropriate, for example geophones for local seismic or rock rupture identification, or monitoring of surface deformations using land- or satellite-based systems.
The steps for the development of a pilot landslide monitoring and early warning system will be: the implementation of in-situ and remote monitoring techniques; use GIS for geo-database or for data analysis and; definition of the alert thresholds through data analysis. The slope stability model implemented in the GIS framework should also be complimented by a risk prediction model to allow for the inherent uncertainty of this data to be directly incorporated in the GIS based analysis algorithms. The risk model implemented may include a decision tree or other decision making tool to allow interpretation of the GIS-based stability predictions (Ansal and Zlatovic, 1999). The risk model will form the framework for issuing warnings or initiating remedial actions, depending on the results of the risk model and the actions defined in the decision tree.
The actual sensors chosen will be determined according to the monitoring needs of the selected test sites. The findings summarised by Crosta and Franttini (2008) in the FP6 LESSLOSS Project will be utilized and efforts will be made to improve the available methodologies.
Task 3. Improvement of the Istanbul Earthquake Rapid Response System with incorporation of new online data and incorporation of new methodologies
Potential impact of large earthquakes on urban societies can be reduced by timely and correct action after a disastrous earthquake. Modern technology permits measurements of strong ground shaking in near real-time for urban areas exposed to earthquake risk. The Istanbul Earthquake Rapid Response System is currently equipped with 100+ instruments and two data processing centres aims at the near real time estimation of earthquake damages using most recently developed methodologies and up-to-date structural and demographic inventories of Istanbul city. For the near-real-time loss estimation systems: GDACS, WAPMERR, PAGER, and NERIES-ELER methodologies are used globally (Erdik et al., 2010).
The Istanbul Earthquake Rapid Response System will be enriched with the incorporation of additional data from the Marmara sea-bottom strong motion recorders and the 100 accelerometers being installed at the district regulators of the Istanbul gas distribution network (EU FP7 REAKT project).
The current methodology used for the near real time estimation of Shake Maps and losses after a major earthquake in İstanbul (Loss Maps) will be improved by: (1) developing faster estimation techniques of the ground motion distribution using the strong ground motion data gathered from the instruments; (2) improvement of the ground motion estimations as earthquake parameters become available and (3) updating the techniques for the estimation of building damage and casualties (together with their uncertainties) for given ground motion (Sesetyan et al.,2010).
The reduction of uncertainties in the basic ingredients of earthquake loss assessment will be tackled to ensure the reliability of the rapid loss assessments in Istanbul. The results of the relevant EU projects (such as NERIES, SAFER, NERA and REACT) as well as the Global Earthquake Model (www.globalquakemodel.org) will be utilized.
Task 4. Seismic Vulnerability Integration and GEO Showcase
The GEO C2 component “Geohazards Monitoring, Alert, and Risk Assessment” in GEO WP 2012-2015, is where currently the Supersite concept is addressed and defined in GEO. In the objective statements of C2 we find “Support global earthquake risk assessment. Improve global standards and establish regional programs for hazard and risk assessment in a global framework”; hazard understanding and monitoring has to be accompanied by an analysis of vulnerability aspects. Seismic hazard and vulnerability constitute the most important components of the seismic risk, as addressed by the Supersite initiative. As such, the seismic vulnerability needs to be fully addressed for the proper estimation of the risk. This needs not entail a giant effort towards mapping vulnerability, as a significant step forward can be achieved by just focusing hazard analysis on areas where vulnerability is significantly present. Further steps in specifying vulnerability distribution will be attained by sourcing vulnerability data and models from the GEM (Global Earthquake Model Project) archive, which features an open model to data access. The EUCENTRE has experience and expertise in seismic risk computation and handling, and will define procedures and models to combine hazard and vulnerability information into a more general risk model. This will represent interesting material for a GEO Supersites Showcase, to be disseminated as an effective Supersite application on all-round seismic risk management at the various GEO and GEO-sponsored events, where government representatives may get a feeling of the GEO coordination advantages.