SEARCH · PubMed Health

Results for “Earthquakes”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed2004

Housing reconstruction after two major earthquakes: the 1994 Northridge earthquake in the United States and the 1999 Chi-Chi earthquake in Taiwan.

The idea of pre-impact recovery planning has recently been promoted by researchers and practitioners, but very little research has been done to evaluate its effects on disaster recovery. This study compared two jurisdictions--the city of Los Angeles, California and Taichung county in Taiwan--in their recovery from earthquakes. Although the two cases also differ with respect to variables other than the presence of pre-impact recovery plans, the available data suggest that having a pre-impact recovery plan facilitates housing reconstruction and allows local officials to make more effective use of the window of opportunity after disaster to integrate hazard mitigation into the recovery process.

Disaster Planning↗

PubMed2001

Were there enough physicians in an emergency department in the affected area after a major earthquake? An analysis of the Taiwan Chi-Chi earthquake in 1999.

STUDY OBJECTIVE: The purpose of this study was to evaluate physician manpower and mobilization in an urban emergency department receiving patients after a major earthquake. METHODS: Patient charts were reviewed. The workload of physicians was assessed semiquantitatively before and after a major earthquake. The physicians' mobilization in the postearthquake emergency response was assessed by using a confidential questionnaire. RESULTS: In the 3 days after the earthquake, 566 patients with earthquake-related illnesses or injuries were sent to the urban ED. Three hundred one (53.2%) patients arrived within the initial 10 hours. In the initial hours, there was no significant difference between the number of patients per physician per hour before and after the earthquake. Workloads of wound treatment and advanced life support procedures were significantly higher after the earthquake compared with before the earthquake, during the first to sixth hour and second to fifth hour, respectively. Sixty-five percent of the hospital's physicians did not assist in either the ED or in any other parts of the hospital in the initial 6 hours after the earthquake. CONCLUSION: The number of physicians in the ED was insufficient in the initial hours after the earthquake because of the sudden influx of a large number of patients. Future disaster planning must address the issue of physicians' behavior with regard to their priorities immediately after a major earthquake and include greater provision for efficient mobilization of physicians.

Disasters↗

PubMed2005

Earthquake-related psychological distress and associated factors 4 years after the Parnitha earthquake in Greece.

Exposure to earthquakes has been associated with psychological distress and in particular the development of post-traumatic stress disorder (PTSD). Earthquake-related psychological distress can be longstanding. The present study involved 157 Greek survivors of the 1999 Parnitha earthquake assessed approximately 4 years after the earthquake. Assessments were based on the Traumatic Stress Symptom Checklist (TSSC). Using stringent calibrations for the estimation of symptom presence 25% of the survivors endorsed at least 5 and 12% at least 10 TSSC symptoms. Approximately 22% of the survivors reported subjective distress and 15% impaired adjustment due to their symptoms. Intensity of fear during the earthquake and participation in rescue operations related to greater post-earthquake psychological distress. The results suggest that the psychological consequences of earthquakes can be serious and long-standing even when the magnitude of the earthquake is moderate. Psychological treatments that have been proven to reduce fear and PTSD symptoms need to be made available to the survivors. Such treatments may also increase the survivors' psychological preparedness and emotional resilience in view of future earthquakes.

Adjustment Disorders↗

PubMed2000

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.

California↗

PubMed2000

Change in the probability for earthquakes in Southern California due to the Landers magnitude 7.3 earthquake.

The Landers earthquake in June 1992 redistributed stress in southern California, shutting off the production of small earthquakes in some regions while increasing the seismicity in neighboring regions, up to the present. This earthquake also changed the ratio of small to large events in favor of more small earthquakes within about 100 kilometers of the epicenter. This implies that the probabilistic estimate for future earthquakes in southern California changed because of the Landers earthquake. The location of the strongest increase in probability for large earthquakes in southern California was the volume that subsequently produced the largest slip in the magnitude 7.1 Hector Mine earthquake of October 1999.

Journal Article↗

PubMed1997

Earthquake-induced potentiation of acute risk factors in hypertensive elderly patients: possible triggering of cardiovascular events after a major earthquake.

OBJECTIVES: We sought to investigate the potentiation of acute risk factors after the Hanshin-Awaji earthquake (7.2 on the Richter scale). BACKGROUND: The frequency of cardiovascular events increases just after a major earthquake, but the causative factors have not been fully investigated. METHODS: We studied the changes in cardiovascular risk factors in 42 elderly outpatients with well-controlled hypertension living near the epicenter (Awaji-Hokudan districts) 7 to 14 days after the earthquake when the major felt-aftershocks persisted. They all experienced the highest stress grading of 6 (catastrophic stress) according to the DSM-III-R. To study the hemostatic profile and endothelial cell state, we measured the blood pressure (BP), hematocrit and lipid profiles as well as fibrinogen, a marker of fibrin turnover (D-dimer), fibrinolytic factors (plasmin-alpha2-plasmin inhibitor complex [PIC], tissue-type plasminogen activator [t-PA] antigen and t-PA inhibitor [PAI] activity) and an endothelial cell-derived marker (von Willebrand factor [vWF]). RESULTS: Systolic and diastolic blood pressures and other variables increased after the earthquake. Before and after the earthquake, the median (25th to 75th percentiles) systolic BP was 152 (range 142 to 164) and 170 mm Hg (range 161 to 178), respectively (p < 0.0001), and the diastolic BP was 83 (range 79 to 88) and 91 mm Hg (range 84 to 96), respectively (p < 0.0001). Of blood viscosity determinants, hematocrit was 38.1% (range 40.7% to 35.9%) and 39.7% (range 42.9% to 38.3%), respectively (p < 0.001), and fibrinogen 316 (range 272 to 360) and 335 mg/dl (range 307 to 391), respectively (p < 0.05). Von Willebrand factor was 128% (range 74% to 148%) and 148% (range 100% to 178%), respectively (p < 0.01); D-dimer was 410 (range 285 to 633) and 560 ng/ml (range 391 to 888), respectively (p < 0.0001); and PIC was 0.74 (range 0.58 to 0.91) and 0.75 microg/ml (range 0.58 to 1.1), respectively (p < 0.05). In contrast, lipid profiles did not change after the quake. When the patients were classified into the high stress and moderate stress groups according to the degrees of damage to their house and injury to family members, the levels of fibrinogen, vWF, PIC and t-PA antigen were increased only in the former group, whereas BP, hematocrit and D-dimer levels were increased in both groups. These abnormalities of acute risk factors, except for vWF, were transient and decreased to prequake levels by 4 to 6 months after the quake. CONCLUSIONS: Earthquake-induced stress seems to induce transient increases in BP, blood viscosity determinants and fibrin turnover and to prolong endothelial cell stimulation. The potentiation of these acute risk factors might contribute to the occurrence of cardiovascular events just after a major earthquake in elderly subjects with hypertension.

Aged↗

PubMed2001

Earthquake triggering by seismic waves following the Landers and Hector Mine earthquakes.

The proximity and similarity of the 1992, magnitude 7.3 Landers and 1999, magnitude 7.1 Hector Mine earthquakes in California permit testing of earthquake triggering hypotheses not previously possible. The Hector Mine earthquake confirmed inferences that transient, oscillatory 'dynamic' deformations radiated as seismic waves can trigger seismicity rate increases, as proposed for the Landers earthquake. Here we quantify the spatial and temporal patterns of the seismicity rate changes. The seismicity rate increase was to the north for the Landers earthquake and primarily to the south for the Hector Mine earthquake. We suggest that rupture directivity results in elevated dynamic deformations north and south of the Landers and Hector Mine faults, respectively, as evident in the asymmetry of the recorded seismic velocity fields. Both dynamic and static stress changes seem important for triggering in the near field with dynamic stress changes dominating at greater distances. Peak seismic velocities recorded for each earthquake suggest the existence of, and place bounds on, dynamic triggering thresholds. These thresholds vary from a few tenths to a few MPa in most places, depend on local conditions, and exceed inferred static thresholds by more than an order of magnitude. At some sites, the onset of triggering was delayed until after the dynamic deformations subsided. Physical mechanisms consistent with all these observations may be similar to those that give rise to liquefaction or cyclic fatigue.

Journal Article↗

PubMed1996

Rock friction and its implications for earthquake prediction examined via models of Parkfield earthquakes.

The friction of rocks in the laboratory is a function of time, velocity of sliding, and displacement. Although the processes responsible for these dependencies are unknown, constitutive equations have been developed that do a reasonable job of describing the laboratory behavior. These constitutive laws have been used to create a model of earthquakes at Parkfield, CA, by using boundary conditions appropriate for the section of the fault that slips in magnitude 6 earthquakes every 20-30 years. The behavior of this model prior to the earthquakes is investigated to determine whether or not the model earthquakes could be predicted in the real world by using realistic instruments and instrument locations. Premonitory slip does occur in the model, but it is relatively restricted in time and space and detecting it from the surface may be difficult. The magnitude of the strain rate at the earth's surface due to this accelerating slip seems lower than the detectability limit of instruments in the presence of earth noise. Although not specifically modeled, microseismicity related to the accelerating creep and to creep events in the model should be detectable. In fact the logarithm of the moment rate on the hypocentral cell of the fault due to slip increases linearly with minus the logarithm of the time to the earthquake. This could conceivably be used to determine when the earthquake was going to occur. An unresolved question is whether this pattern of accelerating slip could be recognized from the microseismicity, given the discrete nature of seismic events. Nevertheless, the model results suggest that the most likely solution to earthquake prediction is to look for a pattern of acceleration in microseismicity and thereby identify the microearthquakes as foreshocks.

Journal Article↗

PubMed2006

Fatal attraction: living with earthquakes, the growth of villages into megacities, and earthquake vulnerability in the modern world.

The great earthquake belt which stretches from the Mediterranean through the Middle East into Central Asia results from the ongoing collision between the Eurasian plate and the African, Arabian and Indian plates to the south. Through much of this belt, the topography is created and controlled by fault movement in earthquakes. Many habitations are located at the foot of the fault-controlled mountain range-fronts that bound inhospitable deserts or elevated plateaus, in positions that are favourable for trade-routes, strategic control of access or for water supply. As a result, they are vulnerable to earthquakes, which often seem to have targeted population centres precisely. For many centuries, an uneasy accommodation was reached between human needs and the earthquake-controlled landscape, sometimes brilliantly exploited by local hydrological engineering, as in Iran. Occasional earthquakes would occur, killing a shocking proportion of the population, but the populations of the settlements themselves would be relatively small. Many once-small rural communities have now grown into towns, cities or megacities, while retaining their vulnerability through poor building standards. Earthquakes that occur in these places today now kill many more than they did in the past, as we have witnessed in the last few years. Extreme catastrophes have been rare only because the exposure of modern megacities to earthquake hazards has been relatively short (approx. 50 years); an increase in the number of such catastrophes now seems to be inevitable.

Disaster Planning↗

PubMed2003

Is earthquake triggering driven by small earthquakes?

Using a catalog of seismicity for Southern California, we measure how the number of triggered earthquakes increases with the earthquake magnitude. The trade-off between this relation and the distribution of earthquake magnitudes controls the relative role of small compared to large earthquakes. We show that seismicity triggering is driven by the smallest earthquakes, which trigger fewer events than larger earthquakes, but which are much more numerous. We propose that the nontrivial scaling of the number of triggered earthquakes emerges from the fractal spatial distribution of seismicity.

Journal Article↗

PubMed1999

[Factors associated with earthquake deaths in the Great Hanshin-Awaji Earthquake, 1995].

BACKGROUND: In order to find factors associated with earthquake deaths due to the Great Hanshin-Awaji earthquake, we conducted a descriptive epidemiological and a case-control study. METHODS: The study area was Nishinomiya city. Earthquake mortality was calculated by age group, sex and the degree of damage to dwelling. Cases in the case-control study included all 1,104 earthquake-caused deaths. Randomly selected survivors living in the same neighborhood and matching sex, age, and the degree of damage to dwelling were used as controls. Seven kinds of information about subject's health and welfare on January 16, one dey before the earthquake, were used for analysis. RESULTS: The likelihood of earthquake-caused mortality steadily increased after 50 years of age. Mortality among people who lived in completely destroyed dwellings was much higher than that among people who lived in intact or partially-destroyed dwellings. In the case-control study, a significant risk factor for earthquake death was physical disability (odds ratio (OR) = 1.9; 95% confidence interval (95% C.I.), 1.0 to 3.34). When the analysis was limited to those who lived in intact or partially-destroyed dwellings, the odds ratio of physical disability increased to 5.6 (95% C.I., 1.6 to 19.8). CONCLUSIONS: The most important risk factors were age and degree of damage to dwelling. Physical disability was suggested as a risk factor.

Adolescent↗

PubMed1998

[Earthquake-induced stress: relationships and trends noticed in health examination data from survivors of the great Hanshin-Awaji earthquake (Jan. 17, 1995)].

To determine the effects of earthquake-induced stress, health examination data that reflected lifestyle and physical health status were studied. Two groups were examined. In the first group, health examination data was collected in March 1995 after the Great Hanshin-Awaji Earthquake. The participants; 446 individuals (139 male and 307 female aged 50 to 69) were all refugees in the vicinity. Data from the first group were then compared with those from a control group. This group; 1,618 individuals (499 men and 1,119 women aged 50 to 69), were all from the same area, but were examined between April and November 1994 before the earthquake. In the first group, distributions of obese subjects and gender, as well as the mean ages of participants, and mean levels of serum total cholesterol, creatinine and gamma-glutamyltranspeptidase (gamma-GTP) had not significantly changed, although alcohol intake did decrease after the earthquake proportionately. However, subsequent to the earthquake, independent of drinking habits or obesity, mean levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and triglycerides all increased (by 54%, 18%, 27% in men and 22%, 21%, 22% in women, respectively). These data indicate that earthquake-induced stress may influence liver function and lipid metabolism; leading to increased serum transaminase and triglyceride levels. These changes suggest the potential for increased risks of various health impairments for earthquake victims.

Aged↗

PubMed2004

Earthquake nucleation by transient deformations caused by the M = 7.9 Denali, Alaska, earthquake.

The permanent and dynamic (transient) stress changes inferred to trigger earthquakes are usually orders of magnitude smaller than the stresses relaxed by the earthquakes themselves, implying that triggering occurs on critically stressed faults. Triggered seismicity rate increases may therefore be most likely to occur in areas where loading rates are highest and elevated pore pressures, perhaps facilitated by high-temperature fluids, reduce frictional stresses and promote failure. Here we show that the 2002 magnitude M = 7.9 Denali, Alaska, earthquake triggered widespread seismicity rate increases throughout British Columbia and into the western United States. Dynamic triggering by seismic waves should be enhanced in directions where rupture directivity focuses radiated energy, and we verify this using seismic and new high-sample GPS recordings of the Denali mainshock. These observations are comparable in scale only to the triggering caused by the 1992 M = 7.4 Landers, California, earthquake, and demonstrate that Landers triggering did not reflect some peculiarity of the region or the earthquake. However, the rate increases triggered by the Denali earthquake occurred in areas not obviously tectonically active, implying that even in areas of low ambient stressing rates, faults may still be critically stressed and that dynamic triggering may be ubiquitous and unpredictable.

Journal Article↗

PubMed1996

Scale dependence in earthquake phenomena and its relevance to earthquake prediction.

The recent discovery of a low-velocity, low-Q zone with a width of 50-200 m reaching to the top of the ductile part of the crust, by observations on seismic guided waves trapped in the fault zone of the Landers earthquake of 1992, and its identification with the shear zone inferred from the distribution of tension cracks observed on the surface support the existence of a characteristic scale length of the order of 100 m affecting various earthquake phenomena in southern California, as evidenced earlier by the kink in the magnitude-frequency relation at about M3, the constant corner frequency for earthquakes with M below about 3, and the sourcecontrolled fmax of 5-10 Hz for major earthquakes. The temporal correlation between coda Q-1 and the fractional rate of occurrence of earthquakes in the magnitude range 3-3.5, the geographical similarity of coda Q-1 and seismic velocity at a depth of 20 km, and the simultaneous change of coda Q-1 and conductivity at the lower crust support the hypotheses that coda Q-1 may represent the activity of creep fracture in the ductile part of the lithosphere occurring over cracks with a characteristic size of the order of 100 m. The existence of such a characteristic scale length cannot be consistent with the overall self-similarity of earthquakes unless we postulate a discrete hierarchy of such characteristic scale lengths. The discrete hierarchy of characteristic scale lengths is consistent with recently observed logarithmic periodicity in precursory seismicity.

Journal Article↗

PubMed2000

The impact of the earthquake in northwestern Turkey on the continuous ambulatory peritoneal dialysis patients who were living in the earthquake zone.

In August 1999, an earthquake of magnitude 7.8 on the Richter scale hit northwestern Turkey. The epicenter was in Izmit, an industrial town about 60 km from Istanbul. This paper presents data about the fate of CAPD patients who were living in that region at the time of the earthquake. A total of 42 continuous ambulatory peritoneal dialysis (CAPD) patients (14 females, 28 males; 37 adult patients, 5 pediatric patients) were permanent residents of the earthquake region. They were followed in the CAPD units of Marmara University Hospital (n = 6), Gata Military Hospital (n = 2), and Goztepe SSK Hospital (n = 10, including the 5 pediatric patients) in Istanbul, and in Uludag University Hospital in Bursa (n = 6) and Kocaeli University Hospital in Izmit (n = 18). Two CAPD patients, together with their families, died under the rubble in the city of Golcuk. One CAPD nurse from Kocaeli University Hospital in Izmit also died a victim of the earthquake. One patient who lived in Golcuk was under the rubble for 3 hours; she was rescued with no crush injuries and was able to continue with CAPD 24 hours after her rescue. Eight patients reported that their homes were completely destroyed during the earthquake, while nine patients reported serious damage to their houses. Ten patients had to move to other towns to live with relatives because their homes were no longer suitable for habitation, and twelve patients had to stay permanently in tents provided by the Red Cross. All of the patients were able to continue their CAPD therapy and had no interruption in the supply of their CAPD solutions. Four patients on continuous cycling peritoneal dialysis (CCPD) therapy continued to use their HomeChoice machines (Baxter Healthcare Corporation, Deerfield, IL, U.S.A.) even while living in a tent. CAPD patients from the Kocaeli University Hospital had to be temporarily referred to other CAPD centers in Istanbul and Bursa because the Kocaeli University Hospital was seriously damaged in the earthquake. We expect that these major changes in quality of life circumstances will have an important impact on the morbidity of these patients, especially in regard to the rate of peritonitis and the adequacy of dialysis.

Adult↗

PubMed2006

Prevalence of psychiatric disorders three years after the 1999 earthquake in Turkey: Marmara Earthquake Survey (MES).

BACKGROUND: The objective of the study is to describe the community prevalence of psychiatric disorder, mainly posttraumatic stress disorder (PTSD) and Major Depressive Disorder (MDD) 3 years after a devastating earthquake. METHODS: Three years after the Marmara Earthquake, 683 individuals from the epicentre were randomly selected to form a representative sample and were assessed with Composite International Diagnostic Interview (CIDI), General Health Questionnaire (GHQ), Traumatic Stress Symptom Checklist (TSSC) and Beck Depression Inventory (BDI). RESULTS: The 36 months prevalence of PTSD and MDD after the Marmara Earthquake were 19.2% and 18.7% respectively. The current prevalence of PTSD and MDD in the affected community was found to be 11.7% and 10.5%, respectively. PTSD and MDD were the most prevalent disorders after the disaster and showed a decrease over time. However, only 38.9% of the PTSD cases identified at any time over the 3 years were in remission at the 3rd-year. The co-occurrence of MDD with PTSD resulted in a decrease in the rate of recovery from PTSD. MDD was also the most prevalent disorder accompanying PTSD. Of all the subjects 37.5% with PTSD still met the MDD criteria at the 3rd year postearthquake. CONCLUSIONS: In comparison with the data from pre-earthquake national mental health profile, the present study showed that the prevalence of MDD, panic disorder, OCD, GAD, social phobia and special phobias were still higher in the affected region 3 years after the earthquake.

Disasters↗

PubMed2003

A single session with an earthquake simulator for traumatic stress in earthquake survivors.

OBJECTIVE: This study examined the effectiveness of a single session of earthquake simulator-assisted exposure treatment of traumatic stress in earthquake survivors. METHOD: Ten earthquake survivors in Turkey were given one session of exposure to simulated earthquake tremors. Assessments were at pre- and postsession and at 2, 4, 8, and 12 weeks posttreatment. RESULTS: All measures showed significant improvement at all assessments. Eight patients were markedly and two slightly improved at follow-up. CONCLUSIONS: A single exposure session with an earthquake simulator appears to be effective in treating postearthquake traumatic stress. Controlled studies are needed to confirm these findings.

Adult↗

PubMed1998

Earthquake-induced cardiovascular disease and related risk factors in focusing on the Great Hanshin-Awaji Earthquake.

The major earthquake increases cardiovascular disease during the period from night-time to morning, especially in the elderly patients living around the epicenter. Earthquake-induced stress increased BP and blood viscosity determinants, and enhanced fibrin turnover with endothelial cell stimulation in a group of hypertensive elderly subjects. Earthquake might trigger the cardiovascular events through the potentiation of these acute risk factors. Reduction of stress and related acute risk factors in this period may suppress cardiovascular deaths following a major earthquake. Further investigation of the mechanisms triggering cardiovascular events after the a major event such as a major earthquake is a necessary part of the strategy for the prevention of cardiovascular disease.

Aged↗