Analysis of post-disaster damage and disruptive impacts on the operating status of small businesses after Hurricane Katrina

When small businesses are impacted by natural hazard events, hazard and sociological researchers may have access to collect data from a sample of open businesses, in hopes of distilling lessons that might help reduce vulnerability to future disasters. Lessons from demised businesses might be more useful in reducing business closure for increasing business sustainability to disasters. Using interviews from a random sample of 371 open and 126 closed businesses’ experiences with Hurricane Katrina, discrete choice methods examine the relationship between the impact of post-disaster damage, loss of lifelines, types of delays in reopening, and cascading damages on business continuity. This unique sample offers the opportunity to determine whether damage to operating businesses was different than that of demised businesses. Respondents provided pre-Katrina data up through the last interviews in 2013. Results demonstrate that damage may have a short-term effect on operating status; it was associated with immediate demise but had much less effect on longer-term recovery. Additionally, it is evident that there is one path to failure. Businesses that did reopen, but later closed, may have been impacted by a cascade of both exogenous and endogenous shocks.     

High frequency variability of current in the western channel of the Tsushima/Korea Straits

The temporal characteristics and spatial structures of high frequency variability of the current in the western channel of the Tsushima/Korea Straits (TKS) are studied using ADCP data from 10?years along the cruise line of a regular ferry, “Camilla”, between Busan and Hakata. The eddy kinetic energy analysis shows that the high frequency variability has strong seasonal and spatial dependencies. From December to April, the variability is prominent in the entire western channel of the TKS. From July to October, it is enhanced only in the Korean coastal zone. The EOF analysis for the component of the high frequency currents normal to the ferry route illuminates three types of dominant modes, a transport mode and a vortex mode in the western channel during December–April, and a baroclinic coastal-trapped mode in the Korean coastal zone during July–October. The transport mode with a uniform current direction throughout the channel shows good correlation with the high frequency variability of the volume transport through the western channel with dominant time scales of 3.5 and 7?days. The vortex mode with alternating current directions across the channel explains well the variability of the eddy vorticity in the western channel with dominant time scales of 5–8?days. The baroclinic coastal-trapped mode in the Korean coastal zone has characteristics of both baroclinic Kelvin wave and topographic Rossby wave in the vertical current structure with dominant time scales of 14 and 32?days.     

Qualitative analysis and mapping of heavy metals in an abandoned Au–Ag mine area using NIR spectroscopy

Reflectance spectroscopy covering the visible and near-infrared ranges (400–2,400 nm) is known as a rapid and nondestructive method in the characterization and quantitative analysis of many components of interest. In this study, the potential use of spectral absorption feature parameters (SAFPs) in the range of 400–2,400 nm was investigated in terms of the prediction of heavy metals and mapping of their distribution. Parameters such as absorption depth, area, and peak ratio were derived from variations in spectral absorption shape associated with concentrations of heavy metals. Heavy metals were quantified from SAFPs using stepwise multiple linear regression (SMLR) and enter multiple linear regression (EMLR). The EMLR model showed qualitative prediction performance for As and Cu, with R ² values of 0.60 and 0.81, respectively. A contour map of As and Cu concentrations based on EMLR-derived values showed similar spatial patterns to a map based on measured values.     

Behavioral patterns and <Emphasis Type="Italic">in-situ</Emphasis> target strength of the hairtail (<Emphasis Type="Italic">Trichiurus lepturus</Emphasis>) via coupling of scientific echosounder and acoustic camera data

The present study focuses on the influence of target strength (TS) changes in the swimming angle of the hairtail (Trichiurus lepturus). We measured in-situ TS at 38 and 120 kHz with luring lamps at a fishing ground for jigging boats near the coastal waters of Jeju-do in Korea. Swimming angle and size of hairtails were measured using an acoustic camera. Results showed that mean preanal length was estimated to be 13.5 cm (SD = 2.7 cm) and mean swimming tilt angle was estimated to be 43.9° (SD = 17.6°). The mean TS values were ?35.7 and ?41.2 dB at 38 and 120 kHz, respectively. The results will assist in understanding the influence of swimming angle on the TS of hairtails and, thus, improve the accuracy of biomass estimates.     

A simple method of correction for profile-length water-column height variations in high-resolution,shallow-water seismic data

In high-resolution, shallow-water seismic surveys, correction for water-column height variations caused by tides, weather, and currents is an important part of data processing. In this study, we present a very simple method of correction for profile-length (i.e., long-wavelength) water-column height variations for high-resolution seismic data using a reference bathymetric grid. First, the difference between the depth of the seafloor picked from seismic data and the bathymetry from the bathymetric grid is computed at the locations where the shot points of seismic profiles and the bathymetric grid points are collocated or closest. Then, the results are gridded and smoothed to obtain the profile-length water-column height variations for the survey area. Next, the water-column height variations for each seismic profile are extracted from the smoothed grid and converted to two-way traveltimes. The corrections for the remaining mis-ties at the intersections, computed within a circular region around each tie shot point, are added to the corrections for the water-column height variations. The final, mistie corrected water-column height corrections are loaded to the SEGY trace header of seismic data as a total static. We applied this method to the sparker data acquired from the shallow-water area off the western-central part of Korea where the tidal range is over 7 m. The corrections for water-column height variations range from -10 to 4 m with a median value of about -2 m. Large corrections occur locally between and near the islands probably due to the amplification and shortening in tidal wavelength caused by rapid shoaling toward the islands.     

Automation of a laboratory flotation machine for improved performance

A commercial laboratory flotation machine (Denver Model D-12) has been automated for ease of operation and reproducibility. The major features of the system include two plexiglass cells of 4- and 2-1 capacity which are interchangeable for rougher and cleaner flotation, respectively, an electronic level controller and an air-flow rate controller. The level controller can be used for either pulp-level or froth-level control by adjusting the threshold setting. Two mechanical paddles on the sides of each flotation cell can be controlled to adjust the rate of froth removal. Test results demonstrate the reproducibility of the data obtained with the equipment.     

Groundwater Impacts from the M5.8 Earthquake in Korea as Determined by Integrated Monitoring Systems

This paper describes the impacts of the M5.8(5.1) Gyeongju earthquakes on groundwater levels using data obtained from a unique coastal monitoring well. The monitoring strategy integrates conventional water level monitoring with periodic, continuous measurements of temperature and electrical conductivity (EC) within the water column of the well. Another important component of the monitoring system is a new instrument, the InterfacEGG, which is capable of dynamically tracking the freshwater-saltwater interface. Although the system was set up to monitor seawater intrusion related to over-pumping, as well as rainfall and tidal effects, it recorded impacts associated with a large earthquake and aftershocks approximately 241 km away. Seismic energies associated with the M5.8(5.1) Gyeongju earthquakes induced groundwater flows to the monitoring well through fractures and joints in the crystalline basement rocks. Temperature and EC logging data showed that the EC vertical profile declined from an average of approximately 5300 to 4800 μS/cm following the earthquakes. The temperature profile showed a trend toward lower temperatures as the depth increased, a feature not commonly observed in previous studies. Data from the InterfacEGG suggested that the rise in EC was not due to the saltwater intrusion, but from the tendency for brackish water entering the borehole to induce convective mixing at deeper depths as the seismic waves travel through the well-aquifer system. The increase in groundwater levels was caused by pulse of colder, less brackish water flowing into the well because of the earthquake. This behavior reflects an enhancement in rock permeability by removing precipitates and colloidal particles from clogged fractures, which improve the hydraulic connection with a nearby unit with a higher hydraulic head. This study suggests there is value added with a more aggressive monitoring strategy.