You are here

Personalized Hazard Assessments-Limitations

Statement of Limitations

TerrainWorks employs the best available science in its predictions of certain types of hazards/risks. However, users of hazards/risks assessments (whether from TerrainWorks or from other sources) should be aware of the often approximate nature of hazard predictions, the inability to predict certain types of hazards/risks, the inherent uncertainty of predicting any type of hazards/risks, the low resolution or outright lack of data necessary to make accurate predictions and the limitations of scientific understanding of all forms of hazards and risks.

TerrainWorks employs information on hazards/risks available in the public domain (such as wildfires and climate change) and also creates its own information on hazards/risks such as shallow landslides, mudflows and flooding.

Hazards: Something that can cause harm, such as a landslide or a tornado.
Risks: A chance, high to low, that any hazard will actually cause harm.

In TerrainWorks Personalized Hazard Assessments, "hazards" refer to the process that is included in the assessments, such as wildfire, landslide, mudflow etc. and "risk" is the associated relative likelihood of occurrence (low - high) and the potential to cause harm.

Approximate Nature of Hazards/Risk Predictions: General versus Calibrated Local Predictions

Use of remote sensing information to create hazard/risk assessments by TerrainWorks necessitates the use of general models or indicators of hazards/risks, rather than locally calibrated models of hazards/risks that require considerable site-specific information, which is not feasible to obtain over large geographic extents. For example, one of the hazards in TerrainWork's personalized assessments is erosion by shallow landsliding and gullying. A general model of shallow landsliding and gullying uses a combination of slope steepness and hillslope form or curvature. In general, the more steep and more curved a hillside is, the more susceptible to landsliding at that location it is. However, as a general index, it can be interpreted different ways in different environmental settings (see Figure to the right).

TerrainWorks employs general models of hazards/risks, rather than locally calibrated models, although which may be more accurate, is not feasible because of the lack of data across large geographic areas, such as the United States.

Inability to Predict Certain Types of Hazards/Risks

Some types of hazards/risks are more difficult to predict than others because of the absence of subsurface information including faults and other geological features and materials. Consequently, TerrainWorks personalized hazard assessments do not predict certain types of hazards/risks (using the nomenclature of Varnes 1978), including:

Rockfalls or rock topples (defined as abrupt movements of geologic materials, such as rocks and boulders, that become detached from steep slopes or cliffs.

Large, rotational landslides, also referred to as deep-seated landslides and earthflows. This is a slide in which the failure plane is curved concavely upward with slide movement approximately rotational about an axis parallel to the ground surface and transverse across the slide; slide planes may also be approximately parallel to the ground surface. This can include very large landslides in a combination of soil, colluvium and solid or fractured rock, or geologic materials such as glacial sediments. The large landslides can transition into large debris flows or mudflows and travel long distances. Examples include the recent Oso landslide in Washington State, Collbran landslide in Colorado, and the Slumgullion earthflow in Utah. As robust science and technology becomes available to make reasonable predictions for these types of failures, they will be included in TerrainWorks Personalized Hazard Assessments.

Any type of landslide triggered by earthquakes.

Inherent Scientific Uncertainty

There exists large uncertainty in many types of hazards/risks. Generally, models of landsliding for example, are based on empirical information on landslide locations and occurrences. Thus any erosion prediction (including those within TerrainWorks personalized hazard assessments) will contain inaccuracies and limitations because of 1) the relatively short and unique history of storms that triggered erosion and that are used to create the science (e.g., longer and different time periods and larger storms may yield different scientific results, models and understanding) and 2) the incomplete scientific understanding of all erosion mechanisms.  For these reasons, all erosion predictions made by the TerrainWorks/NetMap software will not completely identify all of the potentially erodable areas. 

Low resolution or lack of data.

There is abundant and increasing availability of high resolution topographic data, and other types of digital information such as vegetation, soils, climate and geology. These are used by TerrainWorks in personalized hazard assessments to the extent necessary to make general and relativistic predictions of various hazards/risks. However, the lack of data or low resolution of data that are used in the TerrainWorks predictions of hazards/risks can lead to known and unknown uncertainties in all types of predictions.

Other disclaimers (adapted from TerrainWorks License Agreement).

8.4 The Hazard Assessment is provided “as is”, without warranty of any kind, expressed or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose, and non-infringement, which warranties are hereby expressly disclaimed. In no event shall the Licensor, its officers, directors, employees and third-party suppliers, the authors, copyright holders, creators, distributors or disseminators be liable for any demand, claim, cause of action or suit for damages or other liability, including but not limited to for or in connection with consequential damages, business interruption, loss of profits, loss of business information, personal injury, wrongful death, property damage, etc., whether in an action in contract, tort, product liability or otherwise, arising from, out of or in connection with the Hazard Assessment, even if Licensor has been made aware of the possibility of such damages. The user and any and all third parties, for themselves and their assigns, executors and heirs, in exchange for access to, use and or results of the Hazard Assessment, hereby waive and release any and all demands, claims, causes of action and suits of any kind, including but not limited to consequential damages, in connection with or related to the Hazard Assessment, its use, operation and or results, and agree to hold harmless and to indemnify TerrainWorks, authors, creators, developers, suppliers, distributors and disseminators of the Hazard Assessment and or results thereof of and from any and all suits, causes of action, claims and demands of any kind in connection with or related to the Hazard Assessment or the results thereof, including but not limited to for or in connection with consequential damages. In any event, the liability of Licensor, authors, creators, developers, suppliers, distributors and disseminators of the Software and or results thereof for damages shall not exceed the license fee, if any, paid by you directly to Licensor for use of the Hazard Assessment or its results.