Joachim Post
German Aerospace Center
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Featured researches published by Joachim Post.
Earthquake Spectra | 2014
Christian Geiß; Hannes Taubenböck; Sergey Tyagunov; Anita Tisch; Joachim Post; Tobia Lakes
This paper quantitatively evaluates the suitability of multi-sensor remote sensing to assess the seismic vulnerability of buildings for the example city of Padang, Indonesia. Features are derived from remote sensing data to characterize the urban environment and are subsequently combined with in situ observations. Machine learning approaches are deployed in a sequential way to identify meaningful sets of features that are suitable to predict seismic vulnerability levels of buildings. When assessing the vulnerability level according to a scoring method, the overall mean absolute percentage error is 10.6%, if using a supervised support vector regression approach. When predicting EMS-98 classes, the results show an overall accuracy of 65.4% and a kappa statistic of 0.36, if using a naive Bayes learning scheme. This study shows potential for a rapid screening assessment of large areas that should be explored further in the future.
Natural Hazards | 2013
Matthias Mück; Hannes Taubenböck; Joachim Post; Stephanie Wegscheider; Günter Strunz; Sumaryono Sumaryono; Febrin Anas Ismail
Quantification of building vulnerability to earthquake and tsunami hazards is a key component for the implementation of structural mitigation strategies fostering the essential shift from post-disaster crisis reaction to preventive measures. Facing accelerating urban sprawl and rapid structural change in modern urban agglomerations in areas of high seismic and tsunami risk, the synergetic use of remote sensing and civil engineering methods offers a great potential to assess building structures up-to-date and area-wide. This paper provides a new methodology contextualizing key components in quantifying building vulnerability with regard to sequenced effects of seismic and tsunami impact. The study was carried out in Cilacap, a coastal City in Central Java, Indonesia. Central is the identification of significant correlations between building characteristics, easily detectable by remote sensing techniques, and detailed in situ measurements stating precise building vulnerability information. As a result, potential vertical evacuation shelters in the study area are detected and a realistic vulnerability assessment of the exposed building stock is given. These findings obtained allow for prioritization of intervention measures such as awareness and preparedness strategies and can be implemented in local disaster management.
Journal of Earthquake and Tsunami | 2010
Abdul Muhari; Fumihiko Imamura; Danny Hilman Natawidjaja; Subandono Diposaptono; Hamzah Latief; Joachim Post; Febrin Anas Ismail
This paper describes tsunami disaster mitigation in the West Sumatra region with participatory technology assessment (pTA), which promotes direct interaction among member and experts to discuss issues and reach consensus for mitigation through provision of information and knowledge of science and technology. Two areas were examined: Padang, the capital city; and Painan city, a town in southern West Sumatra Province, Indonesia. Tsunami have damaged these areas at least three times: in 1797, a 5–10-m-high tsunami wave height hit the area; in 1833, a 3–4-m-high tsunami came; and in 2007, an 8.4 Mw earthquake generated a local tsunami with maximum wave height of 1.5 m, as observed near Painan. Because of the high level of tsunami risk resulting from its flat topographic conditions, their respective populations of 820,000 people and 15,000 people are developing tsunami mitigation efforts with support of national institutions and international experts. These cities had different starting points and approaches. Efforts were introduced to produce official tsunami hazards maps. Insights from these lessons and ideas arising from the ongoing process after the 2007 South Sumatra and 2009 Padang earthquakes are discussed herein.
IEEE Geoscience and Remote Sensing Letters | 2015
Hideomi Gokon; Joachim Post; Enrico Stein; Sandro Martinis; André Twele; Matthias Mück; Christian Geiss; Shunichi Koshimura; Masashi Matsuoka
In this letter, a new approach is proposed to classify tsunami-induced building damage into multiple classes using pre- and post-event high-resolution radar (TerraSAR-X) data. Buildings affected by the 2011 Tohoku earthquake and tsunami were the focus in developing this method. In synthetic aperture radar (SAR) data, buildings exhibit high backscattering caused by double-bounce reflection and layover. However, if the buildings are completely washed away or structurally destroyed by the tsunami, then this high backscattering might be reduced, and the post-event SAR data will show a lower sigma nought value than the pre-event SAR data. To exploit these relationships, a rapid method for classifying tsunami-induced building damage into multiple classes was developed by analyzing the statistical relationship between the change ratios in areas with high backscattering and in areas with building damage. The method was developed for the affected city of Sendai, Japan, based on the decision tree application of a machine learning algorithm. The results provided an overall accuracy of 67.4% and a kappa statistic of 0.47. To validate its transferability, the method was applied to the town of Watari, and an overall accuracy of 58.7% and a kappa statistic of 0.38 were obtained.
Natural Hazards | 2013
Stephanie Wegscheider; Tobias Schneiderhan; Alexander Mager; Hendrik Zwenzner; Joachim Post; Günter Strunz
Earthquakes and other sudden onset natural disasters require quick and efficient emergency response. Earth observation (EO) data can make a valuable contribution to emergency response efforts if provided within hours and at the most days after the event. Mechanisms like the International Charter Space and Major Disasters and the European GMES Emergency Response Service provide the necessary basis for an efficient and rapid provision of EO data and damage mapping. This paper provides an overview of earthquake damage assessment methodologies, their potential and their limitations in a rapid mapping context and outlines a methodology for casualty estimation. Two case studies—the 2010 Haiti earthquake and the 2011 Van (Turkey) earthquake—are presented, where DLR’s Center for satellite-based crisis information (ZKI) provided rapid damage maps using a team-based visual interpretation approach. Additionally, the application of a casualty estimation method in the immediate aftermath of an earthquake is outlined.
Zeitschrift für Geomorphologie, Supplementary Issues | 2010
M. Rokhis Khomarudin; Günter Strunz; Ralf Ludwig; Kai Zoßeder; Joachim Post; Widjo Kongko; Widodo S. Pranowo
Summary. Th e Indian Ocean Tsunami 2004 dramatically showed the catastrophic consequences when destructive tsunami waves are striking coastal areas. Moreover, it became clear that there is an urgent need for tsunami early warning systems to be set up together with appropriate awareness raising and preparedness activities. In response to this catastrophic event and under the coordination by the UNESCO Intergovernmental Oceanographic Commission the Indian Ocean countries are jointly working on the development, implementation and operation of a tsunami early warning system and the realization of disaster risk assessment and preparedness activities. A crucial component in disaster risk management is the availability of reliable information on the population distribution in the tsunami hazard zones in order to mitigate the impact of natural disasters. Th e mapping of tsunami hazard zones and the estimation of people exposure will help the government to improve the evacuation planning and to decrease the amount of people at risk. Th is paper presents research results developed in the framework of the German-Indonesian Tsunami Early Warning System project focussing on the west coast of Sumatra, the south coast of Java, and Bali. Th e methodology for the determination of the hazard zones is based on a multiscenario approach. For the estimation of the population distribution a method is applied that combines statistical data with land use information in order to disaggregate the census data proportionally. Th is approach provides estimates for day- and night-time population in the hazard zones. Th e hazard and exposure maps are provided for the whole coastal regions and, in more detail, for the study areas Padang, Cilacap and Kuta. Moreover, essential key parameters of this analysis are integrated in the Decision Support System of the Indonesian Tsunami Early Warning Centre.
international geoscience and remote sensing symposium | 2012
Joachim Post; Shunichi Koshimura; Stephanie Wegscheider; Abdul Muhari; Matthias Mück; Günter Strunz; Hideomi Gokon; Satomi Hayashi; Enrico Stein; Andrius Ramanauskas
The paper outlines new research findings and hereof generated products in the field of earth observation and modeling technologies to support emergency response measures. Based on the recent earthquake and tsunami disaster in Japan (March 2011) examples will be given for new methodological developments and products to support emergency response strategies more effectively.
international geoscience and remote sensing symposium | 2014
Hideomi Gokon; Shunichi Koshimura; Joachim Post; Christian Geiß; Enrico Stein; Masashi Matsuoka
In this study, a semi-automated method to estimate building damage in a tsunami affected area is developed using pre- and post-event high-resolution synthetic aperture radar (TerraSAR-X) data. For development, some coastal areas affected by the 2011 Tohoku earthquake tsunami were focused. The method for estimating building damage consists of three steps, 1) To detect flooded areas by the tsunami, 2) To detect built-up areas, 3) To estimate building damage inside the flooded built-up areas. The previously proposed methods using high-resolution SAR data needs building footprint data for estimating building damage[1]. However, this problem was improved by developing a new method which does not need building footprint data to estimate building damage caused by the tsunami. The developed method was validated on the other test sites and the estimated results showed good consistency with the ground truth data.
international conference on modeling simulation and applied optimization | 2013
Franz Hummel; Joachim Post; Günter Strunz; Ralf Ludwig; Annemarie Hoffmann; Sihem Benabdallah
The project CLIMB (Climate Induced Changes on the Hydrology of Mediterranean Basins - Reducing Uncertainty and Quantifying Risk through an Integrated Monitoring and Modeling System, www.climb-fp7.eu) investigates the impacts of climate change on hydrological quantities and the occurrence of extreme events for the Mediterranean Region and neighboring countries. This study gives insights into setting up the “Water balance Simulation Model” WaSiM in Chiba basin, situated in the north-east of Tunisia. Besides that, the intended climate change impact assessment framework for this region is presented which also includes uncertainty information within the climate and hydrological modeling chain. Finally, some preliminary results are presented which indicate a considerable decline of total available water and associated risks in the study area between the reference (1971-2000) and scenario period (20412070).
SPIE Conference on Remote Sensing for Environmental Monitoring, GIS Applications, and Geology | 2009
Hannes Taubenböck; Michael Wurm; Joachim Post; Achim Roth; Günter Strunz; Stefan Dech
The occurrence of a tsunami, a set of oceans waves caused by any large, abrupt disturbance of the sea surface, hitting a vulnerable system on land can cause massive loss of life, destruction of coastal infrastructure and disruption of economic activity. Vulnerability assessment and risk modelling are important components for an effective end-to-end hazard early warning system and therefore contribute significantly to disaster risk reduction. The focus of this study is on the capabilities and synergistic usage of multisensoral remotely sensed data to contribute to these complex tasks. We use medium and high resolution optical satellite data (Landsat and Ikonos), high resolution radar data from TerraSAR-X as well as a digital elevation model to provide multiple products for the assessment of spatial vulnerability in case of a tsunami impact on the heterogeneous and highly structured coastal urban area of Padang, Indonesia. Results include physical indicators like dimension and location of urbanization, quantification of potentially affected buildings, the identification of safe areas as well as a time-dependent population assessment.