Detailed Damage Assessment Research Articles

A Framework to Predict Community Risk from Severe Weather Threats Using Probabilistic Hazard Information (PHI)

Community assets, including physical structures and critical infrastructure, provide the essential services that underpin our communities. Their destruction or incapacitation from severe weather threats such as hail and tornadoes can have a debilitating impact on a community’s quality of life, economy, and public health. Recently, prototype Probabilistic Hazard Information (PHI) from the NOAA Forecasting a Continuum of Environmental Threats (FACETs) program has been developed to reflect the rapidly changing nature of severe weather threats to support forecasters, emergency management agencies, and the public. This study develops a holistic framework to merge PHI with a geodatabase of local infrastructure and community assets to predict possible impacts during events and to assist with post-event recovery. To measure the degree of damage of each building, this study uses the predicted intensity from forecasters along with damage indicators from the Enhanced Fujita scale for a range of wind speeds associated with the predicted intensity. The proposed framework provides the possibility of (1) live prediction of risks to community assets due to local vulnerability, and (2) provision of detailed damage assessments, such as degree of damage of systems or assets, and affected areas, to emergency agencies, infrastructure managers, and the public immediately following an event. With further refinement and verification, this community risk assessment prediction may be able to better communicate possible impacts and improve community resiliency from severe weather threats by supporting multiple phases of emergency management, including preparedness, response, and recovery.

A new protocol for estimation of woody aboveground biomass in disturbance-prone ecosystems

Almost one third of global drylands are open forests and savannas, which are typically shaped by frequent natural disturbances such as wildfire and herbivory. Studies on ecosystem functions and services of woody vegetation require robust estimates of aboveground biomass (AGB). However, most methods have been developed for comparatively undisturbed forest ecosystems. As they are not tailored to accurately quantify AGB of small and irregular growth forms, their application on these growth forms may lead to unreliable or even biased AGB estimates in disturbance-prone dryland ecosystems. Moreover, these methods cannot quantify AGB losses caused by disturbance agents. Here we propose a methodology to estimate individual- and stand-level woody AGB in disturbance-prone ecosystems. It consists of flexible field sampling routines and estimation workflows for six growth classes, delineated by size and damage criteria. It also comprises a detailed damage assessment, harnessing the ecological archive of woody growth for past disturbances. Based on large inventories collected along steep gradients of elephant disturbances in African dryland ecosystems, we compared the AGB estimates generated with our proposed method against estimates from a less adapted forest inventory method. We evaluated the necessary stepwise procedures of method adaptation and analyzed each step’s effect on stand-level AGB estimation. We further explored additional advantages of our proposed method with regard to disturbance impact quantification. Results indicate that a majority of growth forms and individuals in savanna vegetation could only be assessed if methods of AGB estimation were adapted to the conditions of a disturbance-prone ecosystem. Furthermore, our damage assessment demonstrated that one third to half of all woody AGB was lost to disturbances. Consequently, less adapted methods may be insufficient and are likely to render inaccurate AGB estimations. Our proposed method has the potential to accurately quantify woody AGB in disturbance-prone ecosystems, as well as AGB losses. Our method is more time consuming than conventional allometric approaches, yet it can cover sufficient areas within reasonable timespans, and can also be easily adapted to alternative sampling schemes.

Performance of structures in İzmir after the Samos island earthquake.

The October 30, 2020 Earthquake caused unexpectedly significant damage in İzmir considering its distance to the city. This paper evaluates the recorded ground motions, summarizes the performance of structures affected from the earthquake with emphasis on the reasons of damage. A detailed damage assessment was carried out by the Earthquake Engineering Research Center of Middle East Technical University to compile data on the damage of RC and masonry buildings. It was observed that majority of the damage was concentrated in the Bayraklı district due to its peculiar soil properties where many 7–10 story mid-rise RC buildings suffered heavy damage and collapse. The level of amplified ground motions combined with deficiencies of apparently non-code compliant buildings exacerbated the damage. The main reasons of damage were mainly attributed to the presence of soft stories, lack of proper detailing, poor construction quality, presence of heavy overhangs, and hence significant lack of code-compliance in essence. The influence of infill walls on seismic performance of deficient and inadequate buildings was clearly seen in this earthquake. This paper also discusses seismic code requirements in effect and their influence on the observed building performance. The recorded ground motions were compared with the code spectra to evaluate the performance of the buildings. The code response spectra were found to be well above the recorded ground motion spectra at the sites where significant damage was observed.

Elephants in the village: Causes and consequences of property damage in Asia and Africa

AbstractIn recent years, reports of elephants causing damage in rural villages by destroying houses and foraging on stored food have been increasing, but little is known about the determinants and magnitude of this damage. In this study, we have examined the extent of property damage by elephants (Loxodonta africana and Elephas maximus), in one African and two Asian study areas over a six‐year period. A total of 1,172 damaged constructions were observed on site, involving detailed damage assessment by trained enumerators and standardized interviews with witnesses. Depending on the study area, between 67.1 and 86.4% of damage events were attributed to single, individual elephants or pairs of males. The majority of properties were damaged in search for food (62.5–76.7% respectively). Property damage caused higher mean losses than crop damage on farmland in all study areas. Results suggest that property damage by elephants has been largely underestimated and needs to form a focus in future human–elephant conflict research. We suggest a need to reduce the attractiveness of villages by storing food in locked and safe places, away from sleeping areas and to foster the development of elephant safe stores, appropriate to the particular cultural background of the target area.

Deformation of framed structures due to tunnelling – a novel assessment approach

It is common practice to assess the deformation of structures due to tunnelling-induced effects by assuming that foundation movements coincide with greenfield tunnelling movements. This often overestimates the resulting movements and stresses on the structures and may fail to give the correct deformed shape for detailed damage assessment. This paper proposes a novel approach to study the interaction between tunnels and framed structures, based on the translational and rotational stiffness of foundations from the field of seismic engineering. This approach can readily be deployed in routine civil engineering design and tunnelling impact assessment.

Edge Detection Algorithms in Mapping the Condition and Historic Phases of the Last Judgment Mosaics in Torcello/Venice

Whenever innovative survey techniques allow gathering detailed information about fixed building interiors, establishing the conditions, authenticity or the structural problems of historic built in mosaics rests a quite complex process. This paper analyzes the reliability of digital post processing techniques to support distinguishing among application methods, original and remade areas, and for detailed damage assessment. The results are destined to form an interdisciplinary repository regarding the Byzantine mosaics of Torcello as hearth of the Veneto-Byzantine mosaic school of the 13th c.

Component level seismic fragility functions and damage probability matrices for Nepali school buildings

Performance of school buildings during the earthquake is crucial as large number of students are housed in school buildings during the weekdays. Aiming to depict the seismic vulnerability of school buildings in Nepal, large number of databases were collected after the earthquake and the data were processed to depict the seismic vulnerability of school buildings in Nepal. Based on the detailed damage assessment in the affected schools of central Nepal, we have constructed fragility functions and damage probability matrices. We considered three building classes: reinforced concrete, brick masonry, and stone masonry to depict the seismic vulnerability of school buildings.

Experimental Seismic Response of a Japanese Conventional Wooden House Using 2016 Kumamoto Earthquake Records

AbstractImmediately after the 2016 Kumamoto earthquake series, a detailed damage assessment of more than 2,500 wooden houses was conducted at Mashiki Town, Kumamoto. Severe structural and nonstruct...

Observational fragility functions for residential stone masonry buildings in Nepal

This paper outlines the seismic vulnerability of rural stone masonry buildings affected by the 2015 Gorkha earthquake sequence. Summary of field observation is presented first and empirical fragility curves are developed from the detailed damage assessment data from 603 villages in central, eastern and western Nepal. Fragility curves are developed on the basis of 665,515 building damage cases collected during the post-earthquake detailed damage assessment campaign conducted by Government of Nepal. Two sets of fragility functions are derived using peak ground acceleration and spectral acceleration at 0.3 s as the intensity measures. The sum of the results highlights that stone masonry buildings in Nepal are highly vulnerable even in the case of low to moderate ground shaking. The results further indicate that in the case of strong to major earthquakes, most of the stone masonry buildings in Nepal would sustain severe damage or collapse.

Seismic Vulnerability Assessment of Two Nepalese Rana Palaces

The Rana dynasty ruled Nepal from 1846 to 1951 and was responsible for the construction of a number of private and government Neoclassical- or Baroque-style palaces in Kathmandu and other parts of the country. Following the 2015 Gorkha (Nepal) earthquake, detailed damage assessments of these buildings were undertaken by local and international teams. Two case study buildings that suffered moderate structural damage are presented herein, the Kaiser Mahal Palace and the Ananda Niketan Palace. Kaiser Mahal was assessed prior to the 2015 Gorkha earthquake in order to develop potential seismic retrofitting options, and the results are compared with the damage observations made following the Gorkha earthquake. Ananda Niketan was only assessed after the Gorkha earthquake with an extensive damage evaluation, in-situ material testing and sample extraction, and the undertaking of a comprehensive detailed seismic assessment. The two case studies are presented herein, followed by a comparison between the two buildings.

POTENTIAL OF MULTI-TEMPORAL OBLIQUE AIRBORNE IMAGERY FOR STRUCTURAL DAMAGE ASSESSMENT

Quick post-disaster actions demand automated, rapid and detailed building damage assessment. Among the available technologies, post-event oblique airborne images have already shown their potential for this task. However, existing methods usually compensate the lack of pre-event information with aprioristic assumptions of building shapes and textures that can lead to uncertainties and misdetections. However, oblique images have been already captured over many cities of the world, and the exploitation of pre- and post-event data as inputs to damage assessment is readily feasible in urban areas. In this paper, we investigate the potential of multi-temporal oblique imagery for detailed damage assessment focusing on two methodologies: the first method aims at detecting severe structural damages related to geometrical deformation by combining the complementary information provided by photogrammetric point clouds and oblique images. The developed method detected 87% of damaged elements. The failed detections are due to varying noise levels within the point cloud which hindered the recognition of some structural elements. We observed, in general that the façade regions are very noisy in point clouds. To address this, we propose our second method which aims to detect damages to building façades using the oriented oblique images. The results show that the proposed methodology can effectively differentiate among the three proposed categories: collapsed/highly damaged, lower levels of damage and undamaged buildings, using a computationally light-weight approach. We describe the implementations of the above mentioned methods in detail and present the promising results achieved using multi-temporal oblique imagery over the city of L’Aquila (Italy).

POTENTIAL OF MULTI-TEMPORAL OBLIQUE AIRBORNE IMAGERY FOR STRUCTURAL DAMAGE ASSESSMENT

Abstract. Quick post-disaster actions demand automated, rapid and detailed building damage assessment. Among the available technologies, post-event oblique airborne images have already shown their potential for this task. However, existing methods usually compensate the lack of pre-event information with aprioristic assumptions of building shapes and textures that can lead to uncertainties and misdetections. However, oblique images have been already captured over many cities of the world, and the exploitation of pre- and post-event data as inputs to damage assessment is readily feasible in urban areas. In this paper, we investigate the potential of multi-temporal oblique imagery for detailed damage assessment focusing on two methodologies: the first method aims at detecting severe structural damages related to geometrical deformation by combining the complementary information provided by photogrammetric point clouds and oblique images. The developed method detected 87% of damaged elements. The failed detections are due to varying noise levels within the point cloud which hindered the recognition of some structural elements. We observed, in general that the façade regions are very noisy in point clouds. To address this, we propose our second method which aims to detect damages to building façades using the oriented oblique images. The results show that the proposed methodology can effectively differentiate among the three proposed categories: collapsed/highly damaged, lower levels of damage and undamaged buildings, using a computationally light-weight approach. We describe the implementations of the above mentioned methods in detail and present the promising results achieved using multi-temporal oblique imagery over the city of L’Aquila (Italy).

Flood damage assessment of an urban area in Taiwan

In Taiwan, flooding is one of the major natural hazards causing death and millions of dollars of economic losses every year. In order to minimize damage, a detailed and comprehensive flood damage assessment is necessary for both flood control planning and emergency service operations. As such, the objectives of this study were to assess possible flood damages and provide a comprehensive flood risk index for Taichung City in Taiwan. An analytic hierarchy process questionnaire, which included the factors of different land-use types, was designed and answered by 33 experts from governments, industry, and academia in Taiwan. Questionnaire responses were analyzed, and numerical values were allocated for each land-use type. A flood risk index was then produced by combining the potential of inundation and the flood damage scores. Higher flood risk was found along major roads and the main channel of the Fazih River. The methodology used in this study can be applied to most urbanized areas in Taiwan and elsewhere in the world when the required data sets are available.

Automatic modeling method for regional seismic damage assessment of school buildings in Taiwan

This study proposes a new method for regional seismic damage assessment. Automatic modeling is applied to construct models of school buildings from a property database and component models. The capacity curves of school buildings are obtained through numerical simulation of nonlinear structure analysis instead of deriving the capacity curves by substituting parameters derived from a commonly adopted statistical regression approach into a formula. With professionally pre-set settings, detailed regional seismic damage assessment can be performed using a large number of numerical models generated in a short time. The accuracy and reliability of the proposed method is validated by comparing the base shear – roof displacement curve with data from experimental results and ETABS analysis conducted by the National Center for Research on Earthquake Engineering, as well as data obtained using existing damage assessment methods. Reconnaissance report data on school buildings affected in the Chi-Chi Earthquake is also used for further verification. The proposed regional seismic damage assessment method makes structural analysis on individual structures possible to provide a more accurate and detailed damage assessment.

Ground Motion Characteristics of the 2015 Gorkha Earthquake, Survey of Damage to Stone Masonry Structures and Structural Field Tests

On April 25, 2015, a M7.8 earthquake rattled central Nepal; ground motion recorded in Kantipath, Kathmandu, 76.86 km east of the epicenter suggested that the low frequency component was dominant. We consider data from eight aftershocks following the Gorkha earthquake and analyze ground motion characteristics; we found that most of the ground motion records are dominated by low frequencies for events with a moment magnitude greater than 6. The Gorkha earthquake devastated hundreds of thousands of structures. In the countryside, and especially in rural mountainous areas, most of the buildings that collapsed were stone masonry constructions. Detailed damage assessments of stone masonry buildings in Harmi Gorkha had done, with an epicentral distance of about 17 km. Structures were categorized as large, medium and small depending on their plinth area size and number of stories. Most of the structures in the area were damaged; interestingly, all ridge-line structures were heavily damaged. Moreover, Schmidt hammer tests were undertaken to determine the compressive strength of stone masonry, brick masonry with mud mortar for normal buildings and historical monuments. The compressive strengths of stone and brick masonry were found to be 12.38 and 18.75 MPa, respectively. Historical structures constructed with special bricks had a compressive strength of 29.50 MPa. Pullout tests were also conducted to determine the stone masonry-mud mortar bond strength. The cohesive strength of mud mortar and the coefficient of friction were determined.

Automated Poststorm Damage Classification of Low-Rise Building Roofing Systems Using High-Resolution Aerial Imagery

Techniques concerning postdisaster assessment from remotely sensed images have been studied by different research communities in the past decade. Such an assessment benefits a range of stakeholders, e.g., government organizations, insurance industry, local communities, and individual homeowners. This work explores detailed damage assessment on an individual building basis by utilizing supervised classification. In contrast with previous research efforts in the field, this work attempts at predicting the type of damages such as missing tiles, collapsed rooftop, and presence of holes, gaps, or cavities. Various existing and novel intensity-, edge-, and color-based features are evaluated. Additionally, preprocessing steps that automatically correct photometric and geometric differences are proposed. Furthermore, a study on the reliability of high-resolution aerial imagery in damage interpretation is conducted by comparing results with the assessment of expert volunteers. Results show that the proposed damage detection framework is very effective and performs at a level similar to that of the experts. This paper concludes that the type and extent of damage to individual rooftops can be identified with good accuracy from high-resolution aerial images. It is envisaged that the automated tools presented in this paper would play a significant role in rapid posthurricane damage estimation and in helping to better manage rescue and recovery missions.

Combining Structure-from-Motion with high and intermediate resolution satellite images to document threats to archaeological heritage in arid environments

Abstract For millennia, humans have lived in regions which have been and/or are today characterised by arid environmental conditions. Many archaeological sites are therefore located in deserts where they are subjected to specific conditions regarding their preservation, vulnerability, visibility and accessibility. The aim of this paper is to show how data from high and intermediate resolution satellite sensors and ground-based multi-image photogrammetry (Structure-from-Motion) can be combined to document damage to spatially extensive archaeological heritage in arid environments. In this approach, high-resolution satellite images (QuickBird) are used to locate archaeological sites and to verify the type of disturbance. Multiple sequential intermediate resolution satellite images (Landsat 7 ETM+) are used to document the spatial extent and temporal development of surface disturbances at the site and in the surrounding area. Structure-from-Motion (SfM) is used to document damage to a small segment of the archaeological site by creating a very high resolution DEM and orthophoto which are used for detailed damage assessment. The approach is exemplified using damage by off-road vehicles to a large Nasca period geoglyph in the coastal desert of southern Peru. It can be applied to document threats to spatially extensive archaeological sites in arid environments, such as large-scale looting, agricultural expansion or urban and industrial sprawl.

Relationship between the spatial distribution of SMS messages reporting needs and building damage in 2010 Haiti disaster

Abstract. Just 4 days after the M = 7.1 earthquake on 12 January 2010, Haitians could send SMS messages about their location and urgent needs through the on-line mapping platform Ushahidi. This real-time crowdsourcing of crisis information provided direct support to key humanitarian resources on the ground, including Search and Rescue teams. In addition to its use as a knowledge base for rescue operations and aid provision, the spatial distribution of geolocated SMS messages may represent an early indicator on the spatial distribution and on the intensity of building damage. This work explores the relationship between the spatial patterns of SMS messages and building damage. The latter is derived from the detailed damage assessment of individual buildings interpreted in post-earthquake airborne photos. The interaction between SMS messages and building damage is studied by analyzing the spatial structure of the corresponding bivariate patterns. The analysis is performed through the implementation of cross Ripley's K-function which is suitable for characterizing the spatial structure of a bivariate pattern, and more precisely the spatial relationship between two types of point sets located in the same study area. The results show a strong attraction between the patterns exhibited by SMS messages and building damages. The interactions identified between the two patterns suggest that the geolocated SMS can be used as early indicators of the spatial distribution of building damage pattern. Accordingly, a statistical model has been developed to map the distribution of building damage from the geolocated SMS pattern. The study presented in this paper is the first attempt to derive quantitative estimates on the spatial patterns of novel crowdsourced information and correlate these to established methods in damage assessment using remote sensing data. The consequences of the study findings for rapid damage detection in post-emergency contexts are discussed.

High-Resolution Radar Damage Assessment After the Earthquake in Haiti on 12 January 2010

After a disaster such as an earthquake or tsunami it is important to know quickly the dimensions of the damage to human relief work and crisis management. To study the utility of high-resolution radar damage-assessment for this purpose, pre- and post-seismic TerraSAR-X and Cosmo-SkyMed data of the earthquake in Haiti on 12 January 2010 were compared with the results of visual damage assessment, carried out in the framework of the Post Disaster Needs Assessment and Recovery Framework (PDNA). Studied were grid-based methods estimating the average damage, and detailed methods up to building level. On a grid-scale of 200 m, regression analysis of the average normalized difference between pre- and post-seismic data, and the PDNA, results in an average correlation coefficient of up to 0.49 for medium density built-up in TerraSAR-X. Correlation of the shanty areas is lower than for high density built-up. Industrial areas are excluded because of the continuous activity not related to the earthquake. Detailed damage assessment at building level is less hopeful because the correlation per building is low, though improvement is expected from adding information on the boundaries of buildings, if available. To summarize, grid-based average radar damage assessment in the first days after an earthquake event looks promising, but the type of built-up and the period of time between the acquisitions have to be taken into account. For a more detailed assessment on the long term, in working on reconstruction, it is better to rely on other sources.

Comparison of Damage Assessment Maps Derived from Very High Spatial Resolution Satellite and Aerial Imagery Produced for the Haiti 2010 Earthquake

Following the devastating M7.2 earthquake that affected Haiti on 12 January 2010 two types of building damage assessment maps were produced: 1) area-based damage assessments using pre- and post-event satellite imagery and 2) detailed building-by-building damage assessments using post-event aerial photography. In this paper, we compare the reliability and the usability of area-based damage assessment maps from satellite imagery with respect to the detailed damage assessment from aerial data. The main objective is to better understand how cooperative rapid mapping can steer the more detailed assessments that are typical in determining postdisaster recovery and reconstruction efforts. The results of these experiments indicate that damage assessment maps based on satellite data are capable of capturing the damage pattern, mainly in areas with a high level of damaged and many collapsed structures. However, these maps cannot provide the level of information needed for the quantification of damage intensity.