A review on natural and human-induced geohazards and impacts in karst

This paper presents a broad overview, characterization, and visualization of the interaction relationships between 21 natural hazards, drawn from six hazard groups (geophysical, hydrological, shallow Earth, atmospheric, biophysical, and space hazards). A synthesis is presented of the identified interaction relationships between these hazards, using an accessible visual format particularly suited to end users. Interactions considered are primarily those where a primary hazard triggers or increases the probability of secondary hazards occurring. In this paper we do the following: (i) identify, through a wide-ranging review of grey- and peer-review literature, 90 interactions; (ii) subdivide the interactions into three levels, based on how well we can characterize secondary hazards, given information about the primary hazard; (iii) determine the spatial overlap and temporal likelihood of the triggering relationships occurring; and (iv) examine the relationship between primary and secondary hazard intensities for each identified hazard interaction and group these into five possible categories. In this study we have synthesized, using accessible visualization techniques, large amounts of information drawn from many scientific disciplines. We outline the importance of constraining hazard interactions and reinforce the importance of a holistic (or multihazard) approach to natural hazard assessment. This approach allows those undertaking research into single hazards to place their work within the context of other hazards. It also communicates important aspects of hazard interactions, facilitating an effective analysis by those working on reducing and managing disaster risk within both the policy and practitioner communities.

Reviewing and visualizing the interactions of natural hazards

Sinkhole susceptibility mapping using the analytical hierarchy process (AHP) and magnitude–frequency relationships: A case study in Hamadan province, Iran

1. Arabia and the study of the ancient Near East 2. Ecological and environmental diversity in Arabia 3. The formation of Arabian society: 7000 to 3000 BC 4. Eastern Arabia from 3000 to 2000 BC 5. The Bronze Age in western Arabia 6. Eastern Arabia from 2000 to 1300 BC 7. Humans, dromedaries, and the transformation of ancient Arabia 8. Intensification and consolidation: Arabia from 1300 to 800 BC 9. Expansion and engagement: Arabia and the ancient Near East 10. Adaptation and social formation in ancient Arabia.

/pdf/the-archaeology-of-prehistoric-arabia-adaptation-and-social-4b1idbuv07.pdf

The Archaeology of Prehistoric Arabia: Adaptation and Social Formation from the Neolithic to the Iron Age

Sinkholes, subsidence and subrosion on the eastern shore of the Dead Sea as revealed by a close-range photogrammetric survey

With few exceptions, the ground collapses that constitute the karst geohazard in engineering activity in limestone terrains are induced by human activity. Subsidence sinkholes, formed entirely within the soil profile, constitute the most widespread karst geohazard, but are largely induced by engineered works, either directly or accidentally. Water table decline (as a result of pumped abstraction or quarry de-watering) and uncontrolled surface drainage input are the two key factors that induce subsidence sinkholes, especially where both are involved. Collapse sinkholes, formed by failure of bedrock over a cavity, are rare in natural karst landscapes, but may be induced by excessive loading imposed on limestone that lies above an open cave; the risks associated with this geohazard should be eliminated by implementation of an appropriate site investigation that includes proof drilling. Case studies to demonstrate the karst geohazard concern: (1) homes damaged by new sinkholes around a de-watered limestone quarry in Pennsylvania; (2) problems with sinkholes for a railway across dolomite karst in South Africa; (3) collapse of ground in pseudokarst in Guatemala; (4) failure of a viaduct pier into an unseen cave in Florida; (5) estimation of potential sizes of collapse sinkholes along a pipeline route over gypsum karst in Turkey. As hazardous new sinkholes in karst are almost entirely induced by either uncontrolled drainage or excessive loading, they should be largely eliminated by appropriate engineering design and works. These need to be based on a proper understanding of karst ground conditions.

Sinkhole hazard case histories in karst terrains

Karst is a terrain distinguished by its underground drainage, natural cavities and sinkholes. New subsidence sinkholes (both dropout and suffosion) formed within the soil cover constitute the main karst geohazard. Nearly all are induced by increased drainage inputs or by water table decline, and control of the drainage is the primary means of reducing their hazard. Cave collapse and the development of collapse sinkholes in bedrock are less common, and the stability of a cave roof that is thicker than its width means that only those caves at shallow depth create any hazard. Predictions of the locations of caves or potential sinkhole sites are next to impossible, geophysical searches have severe limitations and borehole searches can incur significant costs. Consequently, controlling the drainage on construction projects is usually the most cost-effective means of minimizing the karst geohazard.

Control the drainage: the gospel accorded to sinkholes

Salt only survives at outcrop in desert climates, and southern Iran has more than its share of salt mountains created by rising diapirs. With their white salt cliffs and creeping salt glaciers, these constitute amazing landscapes with collapsing dolines that feed into spectacularly decorated caves.

Salt terrains of Iran

The limestone karst of southern China is among the most extensive and spectacular in the world. Large blocks of fengcong karst consist of clustered conical hills with large caves draining beneath them and their intervening dolines. Isolated towers in the fenglin karst may evolve from the fengcong where input of allogenic sediments maintains alluviation of the base-level plain and hence permits undercutting of the limestone hills. This process appears to take more than 10 million years, and only occurs in areas of slow tectonic uplift.

Guangxi Karst: The Fenglin and Fengcong Karst of Guilin and Yangshuo

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2451.2009.00736.x

Tony Waltham

Papers

Sinkhole hazard case histories in karst terrains

Control the drainage: the gospel accorded to sinkholes

Salt terrains of Iran

Guangxi Karst: The Fenglin and Fengcong Karst of Guilin and Yangshuo

The karst lands of southern China