Spatio-temporal hazard assessment of a monogenetic volcanic field, near México City

Abstract Background Globally, child mortality rate has remained high over the years, but the figure can be reduced through proper implementation of spatially-targeted public health policies. Due to its alarming rate in comparison to North American standards, child mortality is particularly a health concern in Mexico. Despite this fact, there remains a dearth of studies that address its spatio-temporal identification in the country. The aims of this study are i) to model the evolution of child mortality risk at the municipality level in Greater Mexico City, (ii) to identify municipalities with high, medium, and low risk over time, and (iii) using municipality trends, to ascertain potential high-risk municipalities. Methods In order to control for the space-time patterns of data, the study performs a Bayesian spatio-temporal analysis. This methodology permits the modelling of the geographical variation of child mortality risk across municipalities, within the studied time span. Results The analysis shows that most of the high-risk municipalities were in the east, along with a few in the north and west areas of Greater Mexico City. In some of them, it is possible to distinguish an increasing trend in child mortality risk. The outcomes highlight municipalities currently presenting a medium risk but liable to become high risk, given their trend, after the studied period. Finally, the likelihood of child mortality risk illustrates an overall decreasing tendency throughout the 7-year studied period. Conclusions The identification of high-risk municipalities and risk trends may provide a useful input for policymakers seeking to reduce the incidence of child mortality. The results provide evidence that supports the use of geographical targeting in policy interventions.

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A comparison of satellite-based indices for hazard assessment of MSW open dumps using spatial analysis

Waste Management & Research ◽

10.1177/0734242x18815963 ◽

2018 ◽

Vol 37 (3) ◽

pp. 219-236 ◽

Cited By ~ 1

Author(s):

Khalid Mahmood ◽

Zia Ul-Haq ◽

Fiza Faizi ◽

Syeda A. Batol

Keyword(s):

Hazard Assessment ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Moving Average ◽

Vegetation Indices ◽

Temporal Analysis ◽

Zone Size ◽

Vegetation Health ◽

Spatio Temporal ◽

Hazardous Zone

This study compares the suitability of different satellite-based vegetation indices (VIs) for environmental hazard assessment of municipal solid waste (MSW) open dumps. The compared VIs, as bio-indicators of vegetation health, are normalized difference vegetation index (NDVI), soil adjusted vegetation index (SAVI), and modified soil adjusted vegetation index (MSAVI) that have been subject to spatio-temporal analysis. The comparison has been made based on three criteria: one is the exponential moving average (EMA) bias, second is the ease in visually finding the distance of VI curve flattening, and third is the radius of biohazardous zone in relation to the waste heap dumped at them. NDVI has been found to work well when MSW dumps are surrounded by continuous and dense vegetation, otherwise, MSAVI is a better option due to its ability for adjusting soil signals. The hierarchy of the goodness for least EMA bias is MSAVI> SAVI> NDVI with average bias values of 101 m, 203 m, and 270 m, respectively. Estimations using NDVI have been found unable to satisfy the direct relationship between waste heap and hazardous zone size and have given a false exaggeration of 374 m for relatively smaller dump as compared to the bigger one. The same false exaggeration for SAVI and MSAVI is measured to be 86 m and -14 m, respectively. So MSAVI is the only VI that has shown the true relation of waste heap and hazardous zone size. The best visualization of distance-dependent vegetation health away from the dumps is also provided by MSAVI.

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Seismicity associated with 2018 and 2020 hydraulic stimulations at EGS in Helsinki, Finland, shows limited earthquake interaction: Implication for seismic hazard assessment

10.5194/egusphere-egu21-12217 ◽

2021 ◽

Author(s):

Grzegorz Kwiatek ◽

Maria Leonhardt ◽

Patricia Martínez-Garzón ◽

Matti Pentti ◽

Marco Bohnhoff ◽

...

Keyword(s):

Seismic Hazard ◽

Hazard Assessment ◽

Energy Input ◽

Stress Transfer ◽

Seismic Hazard Assessment ◽

B Value ◽

Temporal Distance ◽

Probabilistic Seismic Hazard Assessment ◽

Interevent Time ◽

Spatio Temporal

<p>In this study we investigate the statistical spatio-temporal characteristics induced seismicity associated with two stimulation campaigns performed in 2018 and 2020 in a 6.1 km deep geothermal well near Helsinki, Finland as part of the St1 Deep Heat project. We aim to find out whether the seismic activity is passively responding to injection operations, or whether we observe signatures of significant stress transfer and strong interactions between events. The former suggests stable relaxation of seismic energy proportional to hydraulic energy input, while the latter includes stress transfer as an additional source of stress perturbation, hence implying larger seismic hazard.</p><p>The selected catalogs from 2018 and 2020 stimulation contained in total 60,814 and 4,368 seismic events, respectively, recorded during and after stimulation campaigns and above the local magnitude of M -1.5. The analyzed parameters include magnitude-frequency b-value, correlation integral (c-value), fractal dimension (D-value), interevent time statistics, magnitude correlation, interevent time ratio and generalized spatio-temporal distance between earthquakes. The initial observations suggest significant time-invariance of the magnitude-frequency b-value, and increased D and c-values only at high injection rates, the latter also guiding the rate of seismicity. The seismicity covering the stimulation period neither provide signatures of magnitude correlations, nor temporal clustering or anticlustering. The interevent time statistics are generally characterized with Gamma distribution (close to Poissonian distribution), and the generalized spatio-temporal distance suggest very limited triggering (90% of the catalog was classified as background seismicity). The observable parameters suggest the seismicity passively respond to hydraulic energy input rate with little to no time delay, and the total seismic moment is proportional to total hydraulic energy input. The performed study provides the base for implementation of time-dependent probabilistic seismic hazard assessment for the site.</p>

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