The Landslide and Erosion Risk indicator estimates the probability and historical frequency of landslide events in the vicinity of a monitored site. It answers the question: how prone is this area to slope instability and land movement?
The indicator analyses historical landslide event records from two authoritative global and national databases. Events recorded within a 1 km buffer around the site polygon are counted and used to model the likelihood of future occurrence using a Poisson probability approach. The result is expressed as a risk level from 1 (minimal) to 5 (extreme).
This indicator is inverted: a lower value indicates better conditions. Level 1 means the area has minimal exposure to landslide risk; level 5 signals extreme and historically frequent events.
Landslide risk is particularly relevant for assessing ecosystem stability, soil integrity, and the resilience of biodiversity in areas affected by land movement. It also underpins regulatory disclosures under ESRS (E1-1, ESRS 2 IRO-1, AR 11) for physical climate and nature-related risk reporting.
The indicator is computed from historical landslide event databases combined with a Poisson model for forward-looking probability.
The site polygon is extended by a 1 km spatial buffer and all recorded landslide events falling within this area are counted. The observation window spans from the year of the earliest recorded event to the most recent year in the dataset. A Poisson annual event rate is then calculated, and the 2-year future probability is derived as:
where P = probability of at least one event within 2 years (%), lambda = total recorded events / observation years
The probability is mapped to a risk level 1–5 using fixed thresholds:
| Risk Level | Future Probability (%) | Grade |
|---|---|---|
| 1 | 0–20 | A — Minimal risk |
| 2 | 20–40 | B — Low risk |
| 3 | 40–60 | C — Moderate risk |
| 4 | 60–80 | D — High risk |
| 5 | 80–100 | E — Extreme risk |
Data are sourced from the NASA Global Landslide Catalog (global coverage, 1970–2019) and the ISPRA IdroGeo Landslide Inventory (Italy, 1960–2017), both providing event-level point data.
Gauge. A semicircular gauge displaying the site's computed landslide risk level on a 1–5 scale, accompanied by three summary stat badges.
Purpose: To show the site's current landslide risk level and the underlying data that produced it — historical event count and forward-looking probability — in one view.
Description: The card shows two areas side by side. On the left: three badge-label pairs showing (1) the number of historical landslide events recorded near the site, (2) the computed risk level (1–5), and (3) the 2-year future probability as a percentage. On the right: a semicircular gauge arc colored from green (level 1, minimal risk) to pink-red (level 5, extreme risk), with a marker needle showing the current risk level and a benchmark reference value. A caption below the gauge describes the scale. The card header shows topic badge "E4", sub-topic "E1-1, ESRS 2 IRO-1, AR 11", a tooltip icon, and an optional download button.
2Landslide Risk
How it's calculated: The risk level displayed on the gauge is computed from the historical event count via the Poisson formula described in the Calculation Methodology section. The gauge arc segments are fixed at levels 1–5, each mapped to a quality grade A–E. The past events badge shows the raw count of events within 1 km of the site. The future probability badge shows the 2-year Poisson probability rounded to the nearest integer percent.
Note: This indicator is inverted — lower values indicate better conditions. Level 1 (grade A) = minimal risk; level 5 (grade E) = extreme risk.
Legend:
| Grade | Risk Level | Future Probability | Color |
|---|---|---|---|
| A | 1 | 0–20% | ■ #00A67A |
| B | 2 | 20–40% | ■ #00DF80 |
| C | 3 | 40–60% | ■ #FFD21E |
| D | 4 | 60–80% | ■ #FF8B16 |
| E | 5 | 80–100% | ■ #FF367F |
Interpretation example:
If the gauge shows risk level 2 with 3 past events and 18% future probability, the site has experienced few landslide events historically and modeled probability of a future event within 2 years is low — a relatively safe location for ecosystem investments.
Highlights Table Row. A row in the multi-KPI comparison highlights table showing the landslide risk level for the selected site and its control area.
Purpose: To allow quick comparison of landslide risk across multiple sites in a single table view.
Description: A labeled row showing the landslide risk level (1–5) for the site (ROI) and the control area (CA), color-coded by quality grade. The row label reads "Landslide Risk". The topic tag is WATER.
How it's calculated: Same computation as the gauge above. The value shown is the risk level for the site and the control area.
Note: This indicator is inverted — lower values indicate better conditions.
Interpretation example:
If a site shows 2 and the control area shows 4, the site is in a significantly safer position relative to its surrounding landscape reference.
Assessment Sidebar Row. A grade row in the E4 Biodiversity section of the assessment sidebar, showing the landslide risk grade for the site.
Purpose: To provide a quick letter-grade summary of landslide risk in the broader biodiversity assessment context.
Description: A single row labeled "Landslides" with a colored grade badge (A–E) derived from the risk level. Grade A (green, #00A67A) indicates minimal risk; grade E (pink, #FF367F) indicates extreme risk.
How it's calculated: The letter grade is derived from the risk level (1=A, 2=B, 3=C, 4=D, 5=E).
Note: This indicator is inverted — lower values indicate better conditions.
Interpretation example:
A grade B row means the site has a risk level of 2, corresponding to a 20–40% probability of a landslide event within 2 years — low but not negligible risk.
Detail Card. A summary card in the map tool site detail sidebar showing the landslide risk level alongside event count and future probability.
Purpose: To give users a quick overview of landslide exposure for a site directly from the map view.
Description: A card with a landslide icon, the label "Landslide Risk", the risk level displayed in large text, the number of recorded events, and the future 2-year probability as a percentage.
How it's calculated: Values come directly from the landslide risk computation: the risk level (1–5), the historical event count, and the 2-year future probability percentage.
Note: This indicator is inverted — lower values indicate better conditions.
Interpretation example:
A card showing risk level 4, 12 events, 72% future probability indicates a historically active area with high probability of future slope instability — significant for ESG and land-use risk assessment.
| Source | Provider | Coverage | Resolution | Period |
|---|---|---|---|---|
| Global Landslide Catalog | NASA | Global | Event-level point data | 1970–2019 |
| IdroGeo Landslide Inventory | ISPRA | Italy | Event-level point data | 1960–2017 |
The site polygon is extended by a 1 km spatial buffer. All landslide events from the databases whose location falls within this buffer are queried. The total event count is determined as the number of distinct recorded events.
The observation window is determined dynamically: from the year of the earliest recorded event in the area to the most recent year in the dataset. A Poisson annual event rate is calculated as lambda = total events / observation years. The 2-year future probability is then computed using the Poisson cumulative distribution function.
The probability is mapped to a risk level 1–5 using fixed thresholds (0–20% = level 1, 20–40% = level 2, 40–60% = level 3, 60–80% = level 4, 80–100% = level 5). Each risk level corresponds to a quality grade A–E.
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Nadim, F., Kjekstad, O., Peduzzi, P., Herold, C., & Jaedicke, C. (2006). Global landslide and avalanche hotspots. Landslides, 3(2), 159–173. DOI: 10.1007/s10346-006-0036-1
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Kirschbaum, D.B., Stanley, T., & Zhou, Y. (2015). Spatial and temporal analysis of a global landslide catalog. Geomorphology, 249, 4–15. DOI: 10.1016/j.geomorph.2015.03.016
ISPRA. IdroGeo: Piattaforma italiana sul dissesto idrogeologico. Available at: https://idrogeo.isprambiente.it