OS23B-01 INVITED
Geophysical Hazards and Preventive Disaster Management of Extreme Natural Events
Geophysical hazard is potentially damaging natural event and/or phenomenon, which may cause the loss of life or injury, property damage, social and economic disruption, or environmental degradation. Extreme natural hazards are a key manifestation of the complex hierarchical nonlinear Earth system. An understanding, accurate modeling and forecasting of the extreme hazards are most important scientific challenges. Several recent extreme natural events (e.g., 2004 Great Indian Ocean Earthquake and Tsunami and the 2005 violent Katrina hurricane) demonstrated strong coupling between solid Earth and ocean, and ocean and atmosphere. These events resulted in great humanitarian tragedies because of a weak preventive disaster management. The less often natural events occur (and the extreme events are rare by definition), the more often the disaster managers postpone the preparedness to the events. The tendency to reduce the funding for preventive disaster management of natural catastrophes is seldom follows the rules of responsible stewardship for future generations neither in developing countries nor in highly developed economies where it must be considered next to malfeasance. Protecting human life and property against earthquake disasters requires an uninterrupted chain of tasks: from (i) understanding of physics of the events, analysis and monitoring, through (ii) interpretation, modeling, hazard assessment, and prediction, to (iii) public awareness, preparedness, and preventive disaster management.
OS23B-02 INVITED
Natural and Anthropogenic Hazards and Associated Processes
The Earth is increasingly subject to hazards either from natural causes or anthropogenic influences. As global climate change is on the increase, such hazards may take on increasingly severe forms and become disasters. All such hazards produce atmospheric signatures which are the result of land-ocean-atmosphere interactions. Tropical cyclones, floods, earthquakes, harmful algal blooms, snow avalanches and other hazards are particularly damaging to coastal areas and often threaten coastal megacities. Here, we examine how remote sensing observations from multi sensor platforms and model runs can be used to analyze, track and even to get early information about the onset of such hazards: dust storms, forest fires, harmful algal blooms and tropical cyclones.
OS23B-03
Development of New Approaches of Coastal Geo-Hazards Observation and Warning Systems
Assessment of potential of geo-hazards and their risks to populated coastal areas is becoming an important domain of scientific research and mitigation management. Coastal zone, shelf and continental slope are quickly becoming new major areas of industrial technological development owing to growing population in coastal regions and vast natural resources such as fish, oil, and gas available in these areas. Understanding risks of natural and human-made coastal zone hazards contributes to strengthening the scientific and technological basis of a number of industries including oil/gas production and transport. Traditional ways to evaluate risks of submarine earthquakes and tsunamis (e.g., through analyzing historic data) are often not comprehensive enough and may result in lower estimates of the actual risks of these hazards, while a combined approach provides more accurate evaluations, which may affect significantly human research and industrial activities in the coastal areas. We report here some new ideas, approaches and preliminary results in the development of tsunami warning systems based on a complex monitoring system using the deep-ocean cable installations and bottom observatories located in the vicinity of the oil and gas drilling platforms which are cable connected to data processing centers. Operation of such systems is to be combined with satellite survey as well as with scientific cruise investigations.
OS23B-04 INVITED
Tsunami Hazard Awareness from past Experience and the Differing Vulnerability of Indigenous and Immigrant Coastal Populations
The high mortality rates (10 percent to over 90 percent) amongst tourist and immigrant populations caught in the 2004 Indian Ocean tsunami contrast both with the lower mortality where local warnings were effective, and with historically low mortality rates in several major tsunamis in Papua New Guinea and the South West Pacific. These include early 20th Century events in which responses to the tsunamis were based upon oral traditions that existed amongst indigenous populations. Eyewitness accounts of one of these events, the 1930 Ninigo Islands tsunami in Papua New Guinea, indicate that people in coastal villages recognized warning signs such as initial drawdown of the sea, and evacuated inland before the tsunami struck with intensities comparable to the 2004 tsunami in Thailand. Maximum runups exceeded 15 meters on Karkar Island and were 5 to 10 meters around much of the Bismarck Sea. Although many villages were severely damaged, only 12 people were killed. The mortality rate was less than 1 percent and perhaps as little as 0.1 percent of the population in the inundation zones. Interviews with populations who have lived on coasts for many generations indicate a high level of tsunami awareness including oral traditions of earlier historical events and traditional beliefs regarding tsunamis and earthquakes. The generally low mortality rates in these events indicate that self - warning and voluntary evacuation constitutes a highly effective tsunami mitigation measure amongst indigenous peoples. The challenge today is to develop similar behaviors amongst immigrant and transient populations in tsunami prone areas through Education for Self - Warning and Voluntary Evacuation (ESWAVE): the efforts of volcanologists after the 1985 Armero lahar disaster provide pointers as to how this can be done.
OS23B-05
Land-Ocean-Atmospheric Coupling Associated with Earthquakes
Earthquakes are well known to occur along the plate boundaries and also on the stable shield. The recent studies have shown existence of strong coupling between land-ocean-atmospheric parameters associated with the earthquakes. We have carried out detailed analysis of multi sensor data (optical and microwave remote) to show existence of strong coupling between land-ocean-atmospheric parameters associated with the earthquakes with focal depth up to 30 km and magnitude greater than 5.5. Complimentary nature of various land, ocean and atmospheric parameters will be demonstrated in getting an early warning information about an impending earthquake.
OS23B-06
Tsunami hazard estimates using forecast tools
NOAA's Pacific Marine Environmental Laboratory is developing tsunami modeling tools as part of the real-time tsunami forecast system for NOAA's Tsunami Warning Centers. The models are used in combination with the real-time deep-ocean measurements to produce estimates of tsunami parameters for coastal locations before the wave reaches the coast. This real-time tsunami hazard assessment will help to provide an informative and site-specific warning for coastal communities. Combined with education and mitigation measures, the tsunami forecast and warning will provide an effective means for coastal communities to prevent loss of lives from tsunamis. It will also reduce the chances for unnecessary evacuations due to over-warning. The modeling tools that have been developed for the real-time forecast could be used for the long-term tsunami hazard assessment as well. The forecast models for ocean-wide tsunami propagation and coastal inundation are thoroughly developed and tested to provide the best possible accuracy. These models provide an opportunity for unprecedented quality scope of tsunami hazard assessment for a particular coastal community. Several examples of tsunami hazard assessments using the forecast tools will be presented. http://nctr.pmel.noaa.gov/
OS23B-07
History of Contamination and Coastal Hazards in Western Long Island Sound, N.Y.
The Long Island Sound, estuary borders metropolitan New York at its western end where it has been severely impacted by anthropogenic activities and natural hazards such as storm surges and floods. The waters and sediments of western Long Island Sound (LIS) accumulate many pollutants including heavy metals and organic matter loadings. Seasonal hypoxic conditions are a major water quality problem, not only with regards to the damage to its ecosystems, but also for the important fishing industry that LIS sustains. On June 2006, we surveyed LIS from 73°30'W to 73°50'W from the R/V Hugh Sharp collecting high-resolution subbottom seismic (chirp) profiles, multibeam bathymetric data and 25 gravity cores (up to 3 m long). The total organic carbon (TOC) and mercury contents measured in the sediments confirm that their concentrations systematically increase from east to west towards New York City. Mercury concentrations increase westward from 700 to 1200 ppb with pre-industrial values of 50 ppb. In contrast, TOC concentrations indicate that eutrophied conditions did exist in western LIS prior to industrialization with pre-industrial concentrations of 3.8% in the west. These concentrations increased due to anthropogenic activities to values in excess of 10%. High-resolution chirp and sonar data reveal that bottom circulation in western LIS is constrained by bedrock some of which outcrops near 73°45'W. The LIS western outlet to the East River at 73°55'W is controlled by the narrow, shallow sill of Hell Gate. The funnel shape of LIS and these bedrock constrictions contribute to significantly decrease tidal and wind induced currents from east to west (60 to10 cm/s). We propose that this decrease in flow velocity leads to sediment deposition and to the concentration of pollutants. We further suggest that hypoxic conditions possibly existed prior to anthropogenic activities due to the basin morphology and decreased circulation. Previous studies based on stable O and C isotopes do indeed indicate that it was hypoxic to anoxic. Finally, our measurements indicate that storms/floods also lead to erosion and deposition of pollutants in western LIS. We are developing a chronology to link erosional surfaces and peak abundances in heavy metals to the historical record of storms, and to a longer-term record to document their recurrence intervals. This will form a basis to assess future potential detrimental effects that storms may have on the Long Island Sound estuary due to climate change.
OS23B-08
Optimal Initial Perturbation for El Nino ensemble prediction with Ensemble Kalman Filter
The optimal ensemble perturbation selection method using breeding concepts in Ensemble Kalman Filter (EnKF) assimilation system is developed and forecast skill using the system is examined with hybrid coupled model. Under the perfect model context, seasonal prediction results confirm that selected ensemble perturbations are fast growing, and the ensemble predictions using selected ensemble members guarantee the skillful forecasts than that using other ensemble members. The correlation skill improvement is about 0.1 robust at 6-8 forecast lead month. It is also found that the forecast skill improvements with selected ensemble members are robust when/where signal-to-noise ratio is small. It means that forecast skill improvement by selecting fast growing ensemble perturbation is significant when/where initial uncertainty is large. It also implies the method helps to reduce the intrinsic predictability barriers like ¢®”Ęspring barrier¢®”¾. Similarly, during the El Nino events, the prediction skill improvement is embossed during El Nino onset and decaying phases when initial perturbation grows faster than other periods.