The Global Disaster Alert and Coordination System provides near real-time alerts about natural disasters around the world and tools to facilitate response coordination, including media monitoring, map catalogues and Virtual On-Site Operations Coordination Centre.

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Asgard alert levels

Asgard combines information on the event, the population in the affected area and the vulnerability of that population to derive an alert level that indicates the probability for a catastrophic situation with needs for international humanitarian intervention. The way these three types of information are combined varies with the disaster type.

Earthquakes

Currently, the evaluation of the potential humanitarian impact of earthquakes considers (1) earthquake magnitude (in units reported by source), (2) earthquake depth, (3) population within 100km of epicentre, and (4) national population vulnerability. Elements 1 and 2 are scraped from seismological sources, while elements 3 and 4 are automatically calculated by a GIS based on epicentre location (latitude and longitude), the Landscan population dataset and ECHO's Global Needs Assessment indicator.

The formula for the threshold is calculated as follows. This formula was established based on statistical analysis and minimization of omission and commission errors of historical earthquake disasters.

First, the alert score is calculated:

• P = sqrt (log₁₀ ( Max (Pop100 / 80000, 1)))
  If Pop100 > 80000 (the cut off population threshold), then P is the square root of the 10 logarithm of Pop100/80000.
  This means that we assume an exponential relationship between impact and population, with a cut off of 80000 people within an area of 31415,6 km², or a population density of about 2,5 people per km².
   
• M = Max ( magnitude - 4.5, 0 )
  If the magnitude is above 4.5, then M is the magnitude - 4.5.
  This means that we do not consider earthquakes of a magnitude lower than 4.5. Further, we assume - for strong earthquakes - a linear relationship between impact and magnitude.
   
• V = GNA Index for closest country (a value between 0 and 3)
  If GNA is missing, then V defaults to 0.5.
  The GNA is a combination of 9 socio-economic and historical indicators that are computed based on ranking and classification. The value (between 0 and 3) is not a quantitative value, but qualitative value.

These factors are combined and weighted as follows:

draft_alert_score = (P * M * V^1.5) / 3

This formula gives a higher weight to the vulnerability of the country, therefore emphasizing that prepared and rich countries with good building standards that can be enforced can better cope with earthquakes than other countries. Equivalent earthquakes are more likely to be a disaster in vulnerable countries.

Subsequently, the draft alert score is modified according to the following rules:

• If the magnitude is less than 6, no red alerts can be issued. In other words, if the draft_alert_score is larger than 2, it is set to 2.
• If the earthquake occurred more than 100km deep, the draft_alert_score is reduced by 1.
• If the earthquake occurred deeper than 300km, the draft_alert_score is set to 0, or a green alert.

Finally, the alert score is transformed into an alert level according to the following thresholds:

• Red: more than 2
• Orange: between 1 and 2
• Green: less than or equal to 1

At the same time, the tsunami alert score is calculated (see below).

Tsunamis

Tsunami alerts are generated when an earthquake occurs under water and when the magnitude is sufficient to create a tsunami. However, this does not mean a tsunami is actually generated, because this depends on many other factors including the type of earthquake.

Volcanoes

Volcano alerts are taken from the source (South West Volcano Research Centre), with the exception that the population near the volcano is taken into consideration.

Tropical cyclones

JRC is working on a new model for tropical cyclones. Currently, each observation point (taken from Hawaii University IFA/SOLAR) is evaluated: wind speed (Saffir Simpson Category) and population are combined to create an alert. For the whole storm, the maximum alert for all points (actual and forecasted) is taken.

In the new model, wind speed buffers will be used. This model will be described further when it will be put on-line.

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			Information on this website has been collected from or in participation with the following organisations: EC Joint Research Centre - UNOSAT - Virtual OSOCC - ReliefWeb - WAPMERR © European Communities, 2004-2008 Reproduction authorised provided the source is acknowledged, except for commercial purposes.	Financially supported for 2004-2007 by EC ECHO