Kimberley I. Shoaf

Seismic, structural, and individual factors associated with earthquake related injury

Background: Earthquakes cause thousands of deaths worldwide every year, and systematic study of the causes of these deaths can lead to their prevention. Few studies have examined how multiple types of risk factors are related to physical injury during an earthquake. Methods: A population based case-control study was conducted to examine how individual characteristics, building characteristics, and seismic features of the 1994 Northridge, California, earthquake contributed to physical injury. Cases included fatal and hospital-admitted injuries caused by the earthquake. Controls were drawn from a population based phone survey of county residents. Cases were individually matched to two sets of controls: one matched by age and gender and one matched by location at the time of the earthquake. Results: Individuals over age 65 had 2.9 times the risk of injury as younger people (95% confidence interval (CI) 1.2 to 7.4) and women had a 2.4 times greater risk than men (95% CI 1.2 to 5.1). Location in multiple unit residential and commercial structures each led to increased injury risk compared with single unit residential structures, but the exact estimate varied depending on the control group used. With every increase in ground motion of 10%g, injury risk increased 2.2 times (95% CI 1.6 to 3.3). Conclusions: Controlling for other factors, it was found that individual, building, and seismic characteristics were independently predictive of increased injury risk. Prevention and preparedness efforts should focus on each of these as potential points of intervention.

GIS Mapping of Earthquake-Related Deaths and Hospital Admissions from the 1994 Northridge, California, Earthquake

PURPOSE Earthquakes pose a persistent but unpredictable health threat. Although knowledge of geologic earthquake hazards for buildings has increased, spatial relations between injuries and seismic activity have not been explained. METHODS Fatal and hospital-admitted earthquake injuries due to the 1994 Northridge Earthquake were identified. Geographical Information Systems software was used to map all injury locations. Injuries were analyzed with regard to distance from the earthquake epicenter, the Modified Mercalli Intensity Index, peak ground acceleration, and proportion of damaged residential buildings. RESULTS Injury severity was inversely related to distance from the epicenter and increased with increasing ground motion and building damage. However, injury incidence and severity were not completely predicted by seismic hazard and building damage, and injuries of all severities occurred in a large geographic area. Average distance to the epicenter was smallest for injuries related to falling building parts and largest for cutting/piercing injuries and falls. CONCLUSIONS The injuries from the Northridge Earthquake extended beyond the areas of highest environmental activity. Factors such as age and activity during the earthquake may be equally important in predicting injury from earthquakes as seismic features.

Surviving Two Disasters: Does Reaction to the First Predict Response to the Second?

Respondents (N = 414) studied after a California earthquake were recontacted 4 years later to determine if their prior experience with a disaster impaired or enhanced their ability to deal with a second natural disaster—a slow-onset El Niño weather pattern. Analyses addressed whether being emotionally injured in one disaster influences the extent to which one prepares for a future disaster, whether emotional injuries experienced in one disaster predispose individuals to emotional injury in a subsequent disaster, and whether other disaster-related parameters (physical injury and property damage) are similarly associated across two disasters. Emotional injury both facilitated preparedness, in terms of number of hazard-mitigation activities performed, and predisposed to a subsequent emotional injury. An unexpected finding emerged showing that emotional injury increased the chance of reporting damage in a second disaster—a relationship that was maintained after controlling for emotional injury in the second disaster. The impact of self-reported emotional injury in two sequential disasters on what might be considered a more objective outcome—property damage in the second disaster—underscores the need for a comprehensive assessment of disaster reactions in postdisaster research and across disasters, when possible.

Psychological distress following urban Earthquakes in California

During and following a disaster caused by a natural event, human populations are thought to be at greater risk of psychological morbidity and mortality directly attributable to increased, disaster-induced stress. Drawing both on the research of others and that conducted at the Center for Public Health and Disaster Relief of the University of California-Los Angeles (UCLA) following California earthquakes, this paper examines the extent to which research evidence supports these assumptions. Following a brief history of disaster research in the United States, the response of persons at the time of an earthquake was examined with particular attention to psychological morbidity; the number of deaths that can be attributed to cardiovascular events and suicides; and the extent to which and by whom, health services are used following an earthquake. The implications of research findings for practitioners in the field are discussed.

Suicides in LOS Angeles County in relation to the Northridge earthquake.

INTRODUCTION Recently, there has been speculation that suicide rates increase after a disaster. Yet, in spite of anecdotal reports, it is difficult to demonstrate a systematic relationship between suicide and disaster. Suicides are fairly rare events, and single disasters rarely have covered geographic areas with large enough populations to be able to find statistically significant differences in such relatively rare events (annual suicide rates in the United States average 12/100,000 population). HYPOTHESIS Suicide rates increased in the three calendar years (1994-1996) following the Northridge earthquake as compared to the three calendar years (1991-1993) prior to the earthquake. Likewise the suicide rates for 1993 are compared with the rates in 1994. By looking at the suicide rates in a three-year period after the earthquake, the additional disasters that befell Southern California in 1995 and 1996 may have had an additive effect on psychological disorders and suicide rates that can be measured. METHODS Data on suicide mortality were compiled for the years from 1989 through 1996. Differences in rates for 1993 compared with 1994 and for three-year periods before and after the earthquake (1991-1993 vs. 1994 -1996) were analyzed using a z-statistic. RESULTS There is a statistically significant difference in the rates for the years prior to the earthquake (1991-1993) when pooled and compared to the suicide rates for the years after the earthquake (1994-1996). The rates of suicide are lower in the three years following the earthquake (11.85 vs. 13.12/100,000 population) than they are in the three years prior to the earthquake (z = -3.85, p < 0.05). Likewise, there is a similar difference when comparing 1993 to 1994 (11.77 vs. 13.84, z = -3.57, p < 0.05). The patterns of suicide remain similar over time, with males and non-Hispanic Whites having the highest rates of suicide. CONCLUSION It does not appear that suicide rates increase as a result of earthquakes in this setting. This study demonstrates that the psychological impacts of the Northridge earthquake did not culminate in an increase in the rates of suicide.

The role of public health in disaster preparedness, mitigation, response, and recovery.

1. Research Director, Center for Public Health and Disaster Relief, University of California-Los Angeles 2. Director, Center for Public Health and Disaster Relief, University of CaliforniaLos Angeles and President, World Association for Disaster and Emergency Medicine Correspondence: Kimberly Shoaf, Dr.PH Center for Public Health and Disaster Relief University of California-Los Angeles Los Angeles, California 90024 USA

The ShakeOut scenario: A hypothetical Mw7.8 earthquake on the Southern San Andreas Fault

In 2008, an earthquake-planning scenario document was released by the U.S. Geological Survey (USGS) and California Geological Survey that hypothesizes the occurrence and effects of a Mw7.8 earthquake on the southern San Andreas Fault. It was created by more than 300 scientists and engineers. Fault offsets reach 13 m and up to 8 m at lifeline crossings. Physics-based modeling was used to generate maps of shaking intensity, with peak ground velocities of 3 m/sec near the fault and exceeding 0.5 m/sec over 10,000 km2. A custom HAZUS®MH analysis and 18 special studies were performed to characterize the effects of the earthquake on the built environment. The scenario posits 1,800 deaths and 53,000 injuries requiring emergency room care. Approximately 1,600 fires are ignited, resulting in the destruction of 200 million square feet of the building stock, the equivalent of 133,000 single-family homes. Fire contributes

The Evidence Base for Effectiveness of Preparedness Training: A Retrospective Analysis

87 billion in property and business interruption loss, out of the total

Development of a Training Curriculum for Public Health Preparedness

191 billion in economic loss, with most of the rest coming from shake-related building and content damage (

Impact of the 1994 Northridge earthquake on the utilization and difficulties associated with prescription medications and health aids.

46 billion) and business interruption loss from water outages (