GeNHs: the first natural hazard event database for the Republic of Georgia

In this contribution we present a new natural hazard database for the Republic of Georgia (GeNHs). This database includes a parametric catalogs of five types of natural hazard events (landslide, debris flow, flash flood, windstorm, and hail) causing significant economic loss and casualties in Georgia over the last decades and centuries, respectively. The compilation of these events is innovative as the entire country is covered, and it is timely and may be used by civil protection, risk managers, and other stakeholders in order to provide information for natural hazard and risk management as well as decision-making with respect to effective and efficient mitigation measures.

The data included in the database was collected based on the minimum requirements of data quality. Data quality included information on the order of magnitude for each hazard type and the related frequencies, a magnitude classification and harmonization of the corresponding data was carried out to obtain magnitude classifications. For each natural hazard type and event, the most reliable values of the main parameters were collected and determined from the set of available information. These included date of occurrence (year, month, day), time of occurrence (hour), location of occurrence (geographical coordinates), magnitude and intensity where appropriate, affected area, and associated loss (number of fatalities; losses in terms of economic values).

The database contains the following information. Landslides were collected for the period between 1900 and 2022, with more than 1,500 events. The magnitude of landslides (M_LL) was taken as the logarithm of its volume (in m^3), with a resulting range between 3.0 and 9.0. Debris flows were collected for the period between 1776 and 2022, with more than 800 events. Debris flow magnitudes (M_DF) were taken as the logarithm of the maximum volume (in m^3) of debris material discharged during a single event, with a resulting range between 3.5 and 7.5. Flash floods were collected for the period between 735 and 2022, with more than 950 events. Flash flood magnitudes (M_FF) were taken as the logarithm of the water peak discharge (in m^3/sec), with a range between 1.5 and 4.0. Windstorms were collected for the period between 1946 and 2022, with more than 1,550 events. Windstorm magnitudes (M_HR) were taken as wind speed (in m/s) divided by ten, with a range between 3.0 and 6.0. Hail storms were collected for the period between 1973 and 2022, with more than 1,500 events. Hail storm magnitudes (M_HL) were taken as the hail grain size (in mm) divided by ten, with a range between 0.4 and 11.0.

This database will provide key input for further improvements of hazard and risk assessment, for the assessment of human and economic losses resulting from such hazards, for assessing possible effects of climate change as well as for evaluating new forecasting and early-warning efforts. The GeNHs database will be accessible online and will be kept updated in the future.