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Sang-Ho Yun

Sang-Ho Yun
NASA · Section of Radar Science and Engineering

Doctor of Philosophy

About

88
Publications
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1,549
Citations

Publications

Publications (88)
Preprint
This article presents a framework for semi-automated building damage assessment due to earthquakes from remote sensing data and other supplementary datasets, while also leveraging recent advances in machine-learning algorithms. The framework integrates high-resolution building inventory data with earthquake ground shaking intensity maps and surface...
Article
Full-text available
The synthetic aperture radar (SAR) imagery has been widely applied for flooding mapping based on change detection approaches. However, errors in the mapping result are expected since not all land-cover changes are flood-induced, and those changes are sensitive to SAR data, such as crop growth or harvest over agricultural lands, clearance of foreste...
Article
Satellite remote sensing is playing an increasing role in the rapid mapping of damage after natural disasters. In particular, synthetic aperture radar (SAR) can image the Earth's surface and map damage in all weather conditions, day and night. However, current SAR damage mapping methods struggle to separate damage from other changes in the Earth's...
Preprint
Satellite remote sensing is playing an increasing role in the rapid mapping of damage after natural disasters. In particular, synthetic aperture radar (SAR) can image the Earth's surface and map damage in all weather conditions, day and night. However, current SAR damage mapping methods struggle to separate damage from other changes in the Earth's...
Chapter
In volcanology, remote sensing provides a global observation framework that is becoming increasingly valuable at multiple spatio-temporal scales. Satellite observations have improved monitoring for even the most remote volcanoes, provided a large-scale context to extrapolate field-based observations, and is now routinely used to characterize and mo...
Article
The Great 2011 Thailand flood is one of the most catastrophic flood disasters recorded worldwide in modern history, which covered about 100,000 km² of the country and resulted in 813 casualties and incurring US$ 46 billion in economic losses. In this paper, we re-evaluate the flood event to identify the root source of the catastrophe. By analyzing...
Article
Shaking from the 6 July 2019 Mw 7.1 Ridgecrest, California, mainshock was strongly felt through southern California, but generated relatively minimal structural damage in Ridgecrest. We consider the extent to which a damage proxy map (DPM) generated from satellite-based Synthetic Aperture Radar images can detect minor damage throughout the town of...
Article
Full-text available
A series of four Mw>6 earthquakes struck the northern region of Lombok, eastern Indonesia, in a span of three weeks from late July to mid-August 2018. The series was thought to be associated with the Flores thrust, but the exact mechanism causing the unusual earthquake series has remained elusive. Our Interferometric Synthetic Aperture Radar analys...
Article
Full-text available
Rainfall-induced floods often cause significant loss of life as well as damage to infrastructure and crops. Synthetic Aperture Radar (SAR) Earth Observation Satellites (EOS) can be used to determine the extent of flooding over large geographical areas. Unlike optical sensors, SAR instruments are suitable for cloudy weather conditions, making them s...
Article
Full-text available
While unprecedented amounts of building damage data are now produced after earthquakes, stakeholders do not have a systematic method to synthesize and evaluate damage information, thus leaving many datasets unused. We propose a Geospa-tial Data Integration Framework (G-DIF) that employs regression kriging to combine a sparse sample of accurate fiel...
Article
Full-text available
Sudden breaching of a saddle dam on July 23, 2018, on the perimeter of the Xe Nammoy hydroelectric-power reservoir, recently constructed in the Mekong basin, southern Laos, caused catastrophic flooding that resulted in fatalities and displaced thousands of individuals. This study aims to (1) assess the cause of the dam breach, and (2) understand th...
Article
Full-text available
During the aftermath of Typhoon Hagibis, we made flood and damage proxy maps, rapidly derived from synthetic aperture radar (SAR) data using change detection approaches. The maps have large spatial coverage over the Tokyo, Fukushima, Ibaraki, Iwate, and Nagano prefectures of Japan. The maps are also largely in agreement with various validation sour...
Article
We analyzed Synthetic Aperture Radar (SAR) images from Copernicus Sentinel-1A and 1B satellites operated by the European Space Agency and the Advanced Land Observation Satellite-2 (ALOS-2) satellite operated by the Japan Aerospace Exploration Agency and Global Navigation Satellite System (GNSS) data from the Network of the Americas for the 4 July 2...
Article
Full-text available
Damage mapping using Synthetic Aperture Radar (SAR) imagery has been studied in recent decades to support rapid response to natural disasters. Many researches have been developing coherent and incoherent change detection. However, their performances can vary depending on the types of the damages, the characteristics of the scatterers and the corres...
Article
Full-text available
The death toll and economic impact of an earthquake can be greatly exacerbated if seismic ground shaking triggers landslides. Earthquake-triggered landslides typically occur in two different contexts: localized failure of steep slopes and resulting landslides that pose a major threat to life in areas below; and lateral spreading of nearly flat sedi...
Article
A nearly 20-year hiatus in major seismic activity in southern California ended on 4 July 2019 with a sequence of intersecting earthquakes near the city of Ridgecrest, California. This sequence included a foreshock with a moment magnitude ( Mw ) of 6.4 followed by a Mw 7.1 mainshock nearly 34 hours later. Geodetic, seismic, and seismicity data provi...
Article
Full-text available
In this study we explored the application of synthetic aperture radar (SAR) intensity time series for urban flood detection. Our test case was the flood in Lumberton, North Carolina, USA, caused by the landfall of Hurricane Matthew on 8 October 2016, for which airborne imagery—taken on the same day as the SAR overpass—is available for validation of...
Preprint
The death toll and economic impact of an earthquake are greatly exacerbated when landslides are triggered by strong ground motion. These slides typically occur in two different contexts: localized failure of steep slopes that pose a major threat to life in areas below; and lateral spreading of nearly flat sediment plains due to shaking-induced liqu...
Article
Full-text available
The kinematics of rift segment linkage in magmatic rifts remain debated. Strain patterns from Afar provide tests of current models of how segmented rifts grow in areas of incipient oceanic spreading. Here, we present a combined analysis of seismicity, interferometric synthetic aperture radar (InSAR), and GPS–derived strain rate maps to reveal that...
Article
Space-based radar observations have transformed our understanding of Earth over the last several decades. Driven by increasingly complex science questions, space radar missions have grown ever more sophisticated with costs rising often to hundreds of millions of dollars. At the other end of the cost and complexity spectrum, CubeSats have emerged in...
Article
Full-text available
We reconstructed the three-dimensional (3D) surface displacement field of the 24 August 2014 M6.0 South Napa earthquake using SAR data from the Italian Space Agency’s COSMO-SkyMed and the European Space Agency’s Sentinel-1A satellites. Along-track and cross-track displacements produced with conventional SAR interferometry (InSAR) and multiple-apert...
Article
Full-text available
This paper presents a new damage-mapping algorithm based on coherence images estimated from multitemporal polarimetric-interferometric synthetic aperture radar (SAR) data. The interferometric coherence has been restricted in the conventional damage-mapping approaches because the decorrelation sources are too complicated to interpret accurately and...
Article
Detection of weak volcano deformation helps constrain characteristics of eruption cycles. We have developed a signal detection technique, called the Targeted Projection Operator (TPO), to monitor surface deformation with Global Positioning System (GPS) data. We have applied the TPO to GPS data collected at Akutan volcano from June 2005 to March 201...
Article
Full-text available
Detection of changes caused by major events—such as earthquakes, volcanic eruptions, and floods—from interferometric synthetic aperture radar (SAR) data is challenging because of the coupled effects with temporal decorrelation caused by natural phenomena, including rain, snow, wind, and seasonal changes. The coupled effect of major events and natur...
Conference Paper
Full-text available
The April 25, 2015 M7.8 Gorkha earthquake caused more than 8,000 fatalities and widespread building damage in central Nepal. Four days after the earthquake, the Italian Space Agency's (ASI's) COSMO-SkyMed Synthetic Aperture Radar (SAR) satellite acquired data over Kathmandu area. Nine days after the earthquake, the Japan Aerospace Exploration Agenc...
Article
Shallow dike intrusions may be accompanied by fault slip above the dikes, a superposition which complicates seismic and geodetic data analyses. The diverse volcano-tectonic and low-frequency local earthquakes accompanying the 2005-2010 large-volume dike intrusions in the Dabbahu-Manda Hararo rift (Afar), some with fault displacements of up to 3 m a...
Article
Change detection using synthetic aperture radar (SAR) data is useful in emergency situations and unfavorable weather conditions. In this letter, change detection using multitemporal polarimetric Uninhabited Aerial Vehicle SAR data is investigated in an urban environment. The most robust polarimetric parameters are determined, and change detection t...
Article
Full-text available
Several current and expected future SAR satellites missions (e.g., TanDEM-X/PAZ, COSMO-SkyMed and Sentinel- 1A/B) are designed as constellations of SAR sensors. Relative to single satellite systems, such constellations can provide greater spatial coverage and temporal sampling thereby enabling better control on interferometric decorrelation and low...
Article
Full-text available
The 25 April 2015 Mw 7.8 Gorkha earthquake caused more than 8000 fatalities and widespread building damage in central Nepal. The Italian Space Agency's COSMO-SkyMed Synthetic Aperture Radar (SAR) satellite acquired data over Kathmandu area four days after the earthquake and the Japan Aerospace Exploration Agency's Advanced Land Observing Satellite-...
Article
Synthetic Aperture Radar Interferometry (InSAR) provides one-dimensional measurements on ground displacement in the radar line-of-sight (LOS) direction. Multiple-Aperture Interferometry (MAI) technique has been successfully used to measure along-track ground displacement. However, the technique occasionally shows filtering boundary artifacts along...
Conference Paper
Full-text available
ARIA (Advanced Rapid Imaging and Analysis) is a joint JPL/Caltech coordinated project to automate InSAR and GPS imaging capabilities for scientific understanding, hazard response, and societal benefit. Under ARIA project we have developed a prototype damage detection algorithm using Interferometric Synthetic Aperture Radar (InSAR) coherence, and th...
Conference Paper
ARIA is a joint JPL/Caltech project to automate synthetic aperture radar (SAR) and GPS imaging capabilities for scientific understanding, hazard response, and societal benefit. We have built a quasi-operational SAR and GPS data system that forms the foundation for hazard monitoring and response capability, as well as providing imaging capabilities...
Conference Paper
Two damaging earthquakes struck California in 2014. The Los Angeles area was shaken by an Mw 5.1 earthquake on 29 March 2014 at 04:10 UTC with an epicenter in La Habra. Damage was concentrated in a zone south of the epicenter. The Italian Space Agency’s (ASI) was acquiring COSMO-SkyMed™ (CSK) synthetic aperture radar (SAR) images of the La Habra ar...
Article
Full-text available
On 24 August 2014, the M 6.0 South Napa earthquake shook much of the San Francisco Bay area, leading to significant damage in the Napa Valley. The earthquake occurred in the vicinity of the West Napa fault (122.313° W, 38.22° N, 11.3 km), a mapped structure located between the Rodger’s Creek and Green Valley faults, with nearly pure right‐lateral s...
Article
Full-text available
As the aerospace industry grows, images obtained from Earth observation satellites have been successfully used in various fields. Specifically, the demand for a high-resolution (HR) optical images is gradually increasing, and hence the generation of a high-quality mosaic image is being magnified as an interesting issue. In this paper, we have propo...
Conference Paper
Full-text available
ARIA is a joint JPL/Caltech project to automate synthetic aperture radar (SAR) and GPS imaging capabilities for scientific understanding, hazard response, and societal benefit. We have built a quasi-operational SAR and GPS data system that forms the foundation for hazard monitoring and response capability, as well as providing imaging capabilities...
Conference Paper
ARIA is a joint JPL/Caltech project to automate synthetic aperture radar (SAR) and GPS imaging capabilities for scientific understanding, hazard response, and societal benefit. We have built a prototype SAR and GPS data system that forms the foundation for hazard monitoring and response capability, as well as providing imaging capabilities importan...
Conference Paper
Full-text available
The Mw 6.0 South Napa Earthquake struck Napa County of California on 24 August 2014 with extensive surface ruptures mapped in the field and with satellite and airborne interferometric synthetic aperture radar (InSAR). The Italian Space Agency’s (ASI) has been acquiring COSMO-SkyMed™ (CSK) synthetic aperture radar (SAR) images of the Napa area since...
Conference Paper
A magnitude 6.0 earthquake struck southern Napa county northeast of San Francisco, California, on Aug. 24, 2014, causing significant damage in the city of Napa and nearby areas. One day after the earthquake, the Advanced Rapid Imaging and Analysis (ARIA) team produced and released observations of coseismic ground displacement measured with continuo...
Article
[1] Dike intrusions both deform Earth's surface and induce propagating earthquake swarms. We develop methods to utilize both deformation and seismicity from brittle, volcano-tectonic earthquakes to image time-dependent dike propagation. Dieterich's (1994) seismicity-rate theory is used to relate dike-induced stress changes to seismicity rate and is...
Article
5-9 March 2011 Kamoamoa fissure eruption along the east rift zone of Kīlauea Volcano, Hawai`i, followed months of pronounced inflation at Kīlauea summit. We examine dike opening during and after the eruption using a comprehensive interferometric synthetic aperture radar (InSAR) data set in combination with continuous GPS data. We solve for distribu...
Article
Full-text available
We have studied the utility of high resolution synthetic aperture radar for levee monitoring using UAVSAR data collected over the dikes and levees in California's Sacramento-San Joaquin Delta and the lower Mississippi River. Our study has focused on detecting and tracking changes that are indicative of potential problem spots, namely deformation of...
Article
Full-text available
The existence of elongated, shallow magma chambers beneath the axes of fast-spreading mid-ocean ridges is well established1–8. Yet, at slow-spreading ridges such shallow and elongated magma chambers are much less evident9,10. Simple thermal models8 therefore predict that spreading velocity and magma supply may provide the main controls on magmacham...
Conference Paper
On March 5, 2011, the Kamoamoa fissure eruption began along the east rift zone (ERZ) of Kilauea Volcano. It followed several months of pronounced inflation at Kilauea's summit and was the first dike intrusion into the ERZ since June 2007. The eruption began in the late afternoon of March 5, 2011 (Hawaii Standard Time; UTC-10:00 hrs) with rapid defl...
Conference Paper
Over the last several years, L-band radar observations from the Japanese ALOS satellite has allowed a variety of crustal deformation studies that give us a taste of what will be possible with a dedicated L-band InSAR mission such as that currently being planned by NASA. Here we illustrate the success (and sometimes failure) of ALOS PALSAR data to m...
Conference Paper
Full-text available
ARIA-EQ is a joint JPL/Caltech coordinated effort to automate geodetic imaging capabilities for hazard response and societal benefit. Over the past decade, space-based geodetic measurements such as InSAR and GPS have provided new assessment capabilities and situational awareness on the size and location of earthquakes following seismic disasters. G...
Conference Paper
Kilauea Volcano, Hawai`i, has a wealth of constantly changing magmatic and structural deformation processes. Interferometric synthetic aperture radar (InSAR) observations provide important constraints on the magmatic and structural source parameters that complement the more sparse in-situ networks of continuous GPS and tiltmeter observations. We pr...
Conference Paper
Under ARIA (Advanced Rapid Imaging and Analysis) project at JPL and Caltech, we developed a prototype algorithm to detect surface property change caused by natural or man-made damage using InSAR coherence change. The algorithm was tested on building demolition and construction sites in downtown Pasadena, California. The developed algorithm performe...
Article
Upgraded GSSR radar is used to generate 5 m resolution imagery of the moon's south polar region and generate 15 m topographic maps. LCROSS impact point identified in the GSSR imagery.
Conference Paper
Large earthquakes cause buildings to collapse, which often claims the lives of many. For example, 2010 Haiti earthquake killed about 230,000 people, with about 280,000 buildings collapsed or severely damaged. When a major earthquake hits an urban area, one of the most critical information for rescue operations is rapid and accurate assessment of bu...
Conference Paper
Guerrero is a province in the southern part of Mexico adjacent to the Pacific Ocean. In the past, large thrust earthquakes have occurred along the interface between the subducting and overriding plates. However, there is a region with a ``seismic gap'' where no earthquakes have occurred since 1911. It is estimated that a rupture of the gap would re...
Article
Kilauea volcano, Hawaii, is highly active with measurable surface deformation that varies over a range of spatiotemporal scales associated with both shallow magma movement and slip on a deeper décollement. We analyze interferometric synthetic aperture radar (InSAR) and continuous GPS time series data from 2003 to 2010 to constrain Kilauea's space-t...
Conference Paper
Earthquake responders need to know where the earthquake has caused damage and what is the likely intensity of damage. The earliest information comes from global and regional seismic networks, which provide the magnitude and locations of the main earthquake hypocenter and moment tensor centroid and also the locations of aftershocks. Location accurac...
Conference Paper
During the 2008-2009 year, the Goldstone Solar System Radar was upgraded to support radar mapping of the lunar poles at 4 m resolution. The finer resolution of the new system and the accompanying migration through resolution cells called for spotlight, rather than delay-Doppler, imaging techniques. A new pre-processing system supports fast-time Dop...
Conference Paper
Mapping the Moon's topography using Earth based radar interferometric measurements by the Goldstone Solar System Radar (GSSR) has been done several times since the mid 1990s. In 2008 we reported at this conference the generation of lunar topographic maps having approximately 4 m height accuracy at a horizontal posting of 40 m. Since then GSSR radar...
Article
Ground displacement measurements from the existing spaceborne interferometric synthetic aperture radar (InSAR) missions have dense coverage in space but sparse sampling in time, with their repeat cycles being 24 days for Radarsat, 35 days for Envisat, and 46 days for ALOS. These month-long sampling periods have been limiting the missions' ability t...
Article
L-band repeat-pass InSAR has been getting scientists' attention for its penetration depth through dense vegetation, revealing the ground deformation under the canopy of forest. This makes it possible to achieve a good coverage of volcanic activities in tropical areas such as Hawaii, Galapagos, and Indonesia. Another advantage of L-band InSAR is its...
Article
Akutan, one of the most active volcanoes in the Aleutian arc, has experienced over 27 eruptive episodes in the last two centuries. The most recent eruptive activity was a series of small steam and ash emissions from March to May 1992. Between 11 and 16 March 1996, more than 3000 earthquakes occurred in Akutan Island. This increase of seismicity was...