Spatio-Temporal Distribution of Rainfall-Induced Landslides in Nicaragua (2000–2022): Preliminary Insights to Communicate Landslide Disaster Risk

Abstract

Nicaragua’s location in the tropics makes it highly susceptible to tropical cyclones, with 22 such events causing significant damage between 1971 and 2020. The attendant risk of landslides and flooding from heavy rainfall associated with these phenomena is a grave concern. However, the absence of consistent policies to progress scientific development due to national socioeconomic and political constraints has impeded effective disaster risk management. This chapter presents an overview of landslide occurrences from 2000 to 2022 and offers preliminary insights for creating strategies to communicate landslide disaster risks.

1 Introduction

Multiple meteorological systems converge in Nicaragua, causing common atmospheric phenomena and heavy rainfall in the Caribbean. Consequently, the country is exposed to the annual impacts of tropical cyclones, which have caused substantial damage over the years. Between 1971 and 2020, 22 cyclones occurred, with 17 classified as hurricanes in categories 1–5, four as tropical storms, and one without an assigned class. The most destructive hurricanes were Mitch in 1998, Felix in 2007, and Joan in 1988, respectively (Velásquez-Espinoza and Alcántara-Ayala 2023).

Moreover, between 1994 and 2013, hydrometeorological events triggered disasters that resulted in yearly losses of US$301.75 million (CRED-UNISDR 2018). This amount is equivalent to an annual loss of 1.71% of the country’s gross domestic product, highlighting the potential significance of major disaster events in the government’s efforts to eradicate extreme poverty and confront the threat of setbacks in development, as emphasized by the World Bank (2021). Therefore, it is imperative to reduce vulnerability and exposure to improve disaster risk management strategies and reduce the economic and social impacts on the affected communities, particularly those associated with floods and landslides.

Recently, Central America experienced two devastating tropical cyclones, Eta and Iota, from November 1 to 18, 2020. The storms caused catastrophic damage to Honduras, Nicaragua, and Guatemala, with winds, flooding, and landslides affecting southern Mexico to northern Colombia. In Nicaragua, Hurricane Eta caused widespread flooding, damaging or destroying 43,000 homes, affecting three million people across 56 municipalities. The storm also caused power cuts, uprooted trees, road blockades, and two deaths in the Bonanza mining area due to a landslide (National Hurricane Centre 2021a; Borrowing Agency 2023).

Hurricane Iota caused damages of $564–741 million in Nicaragua, nearly half of the total damages for Central America. Despite being a Category 4 hurricane, it caused lower damage than anticipated due to landing where Hurricane Eta had already caused destruction. Approximately 900,000 people were affected, with 39 fatalities and 29 missing individuals. Likewise, 160,233 homes lost electricity, 10,000 homes were affected, 47,638 families lacked water services, and 35 communities had no telephone services due to flooding and landslides (EM-DAT n.d.; National Hurricane Centre 2021b; Borrowing Agency 2023).

The historical impact of hurricanes in a country such as Nicaragua, where major development and support to scientific research on disaster risk is still lagging, requires strategies of diverse types, including the continuous development of landslide databases and sound inventories as essential ingredients for landslide hazard and risk assessments. This must be accompanied by initiatives to strengthen population knowledge and sensitivity about landslides’ dynamics, disaster risk drivers and socio-economic and environmental impact.

At the global, national, and local levels, various strategies and initiatives have been implemented to mitigate the risk of landslide disasters. The Sendai Partnerships 2015–2025 (Sassa 2015) and Kyoto Landslide Commitment 2020 (KLC2020) (Sassa 2021) are examples of such efforts, which promote research and capacity building towards disaster risk reduction, with a particular focus on developing countries. Priority Action 5 of KLC2020 emphasizes fostering transparent communication between local governments and society through integrated research, capacity building, knowledge transfer, awareness-raising, training, and educational activities. This approach allows societies and local communities to develop effective policies and strategies for reducing landslide disaster risk, strengthen their capacities for preventing hazards from developing into major disasters, and enhance the effectiveness and efficiency of relief programs (Sassa et al. 2021).

Education and preparedness are widely considered to be among the most significant endeavours to reduce landslide disaster risk effectively. The past decade has seen a renewed importance of enhancing non-structural measures, which aim to reduce disaster risks and impacts through policies and laws, public awareness raising, training, and education, without physical construction (UNISDR 2015, 2017).

Regardless of this necessity, no one has established an integrated strategy for landslide disaster risk communication in Nicaragua to the best of our knowledge. With this in mind, this research proposed preliminary insights for communicating landslide disaster risk.

This chapter is divided into five additional sections to the introduction. Section 2 gives a brief overview of the importance of landslide databases. In the third section, general information about Nicaragua is provided. In the fourth section, the methodological approach is presented. Results and concluding remarks are presented in later sections.

2 Landslide Databases and Inventories

Creating a landslide inventory is paramount when evaluating landslide susceptibility, hazard, and risk. It serves as a vital source of information regarding the location, date, type, size, activity, and causal factors of landslides and the resulting damage. Moreover, they provide a means of storing and analysing spatial and temporal data, allowing for more efficient and effective management of this critical hazard. However, while some countries boast comprehensive inventories, others are developing national or regional databases, signifying varying abilities to conduct national-scale risk assessments (Van Den Eeckhaut and Hervás 2012).

Guzzetti et al. (2012) pointed out that having a record of landslides is important for understanding the impact and scale of landslides in different areas, whether a small area or an entire region. These records help determine the risk and hazard of landslides and analyse the distribution, types, and patterns in relation to the land features. They are also helpful in studying how landscapes change due to landslides. Landslide inventory maps are a valuable tool in evaluating the susceptibility, hazard, and risk of landslides, especially in the early stages of analysis.

The creation of landslide maps is a multifaceted process that involves the use of both traditional and innovative techniques. Traditional methods include field mapping and visual interpretation of aerial photos, whereas innovative methods utilize digital elevation models, satellite images, and new field mapping tools (Guzzetti et al. 2012). By leveraging these diverse methodologies, it is possible to create accurate and informative landslide inventories that aid in identifying and mitigating landslide risks.

In developing countries, national landslide databases often have notable deficiencies in providing essential hazard information, such as the classification, causes, magnitude, accessibility of data regarding the extent of damage, and continuity of information. These inadequacies hinder the ability to accurately assess the risks posed by landslides and take appropriate measures to mitigate their impact. They also hamper reporting progress, such as implementing the Sendai Framework for Disaster Risk Reduction (Bhuiyan et al. 2023).

Recent efforts have also focused on elaborating landslide inventory mapping by combining traditional field survey methods with innovative technology to provide precise and cost-effective information on landslide location, typology, extent, and damage. Participatory mapping involving local communities is particularly effective in areas with scarce data. The resulting data can be used to develop appropriate land-use planning to protect people and infrastructure from landslide hazards (Samodra et al. 2018).

One of the first attempts to understand the spatio-temporal occurrence of landslides in Nicaragua was carried out by Devoli et al. (2007a). This involved the identification of historical landslides before 1990 through research of historical sources at various institutions and the digitalization of landslide spatial locations. The study found that the landslides occurred mostly in combination with other natural phenomena. These were included in a geo-referenced inventory of historical landslide events aimed to provide the basis for a more comprehensive landslide hazard assessment.

Afterwards, Devoli et al. (2007b) compiled a more robust digital database of landslides in Nicaragua in collaboration with the Instituto Nicaragüense de Estudios Territoriales (INETER), foreign development agencies, and other Nicaraguan institutions. The database contains spatial data in the form of geo-referenced points and polygons compiled from various sources, including newspapers, technical reports, and landslide inventory maps. This tool was created to support scientific research to assess landslide hazards and inform emergency management, land-use planning, policy development and early warning systems.

Despite that progress, Devoli et al. (2009) highlighted that the Nicaraguan database lacked reliable data. Therefore, they suggested that more quantitative and qualitative information should be collected during a landslide survey to improve future hazard zoning and risk mitigation. This includes estimates of volume, run-out distance, inundation area, height difference of the landslide deposit, and more sophisticated parameters like the geometrical shift of the centre of mass of the landslide. By gathering this additional information, a better assessment of potential hazards would allow for properly addressing the safety and well-being of at-risk communities.

A key problem with the existing landslide databases in Nicaragua is their lack of wide public direct and friendly accessibility to lay people. This creates legitimate worries about the sources of landslide risk understanding, prevention efforts and disaster response. Without easy access to comprehensive information about the distribution of past and contemporary landslides in space and time, it becomes challenging for non-experts to make informed decisions and take appropriate actions to prevent future disasters. This underscores the need for more transparent and easily accessible databases to help mitigate the impact of landslide disasters in the region, particularly in understanding how to avoid the construction of new landslide disaster risks and disasters.

3 Studied Area

Nicaragua is a Central American country located in the northern hemisphere, between 11°-15° north latitude and 83°-88° west longitude. It is situated in the middle of the isthmus, with coastal plains that rise to central interior mountains. Nicaragua shares land borders with Costa Rica and Honduras (Fig. 1).

Fig. 1

Location of the studied area (own elaboration)

It comprises 15 departments and two autonomous regions: the North and South Atlantic Autonomous Regions. The population comprises diverse ethnic groups, including mestizo (mixed Amerindian and White) 69%, White 17%, Black 9%, and Amerindian 5%. The surrounding oceans mainly influence Nicaragua’s climate, and it receives little precipitation until the formation of TCs (Incer et al. 2000).

Nicaragua boasts a tropical climate that is characterized by two distinct seasons. The “wet” season spans the months of May through October, while the “dry” season occurs between November and April. In the latter half of July and early August, the “Canícula” arrives, marking a period of dryness that interrupts the wet season. Positioned in the path of Pacific cyclones and Atlantic hurricanes, Nicaragua is susceptible to heightened rainfall and strong winds from July to October. Furthermore, the El Niño Southern Oscillation (ENSO) fluctuations can bring varying weather conditions during June and August (CCKP-World Bank n.d.).

It is the largest country in Central America, with a land area of approximately 130,370 km² and a population of 6,948,392 as of 2022. Most of the population, 60%, resides in urban areas, with 67% of the urban population inhabiting slums in 2010. Furthermore, approximately 16,000 individuals have been internally displaced due to disasters. The forested area constitutes 28.3% of the land, while the economically active population is 3,017,985 in 2021 (World Bank 2021).

The Pacific coast has the most economic activity, while the Atlantic coast is less developed. Major export crops are coffee, sugar cane, cotton, bananas, sesame, and peanuts, with rice, beans, corn, and sorghum for domestic consumption (ALADI 2009).

Landslides usually happen on steep slopes of active or dormant volcanoes made of Quaternary volcanic rocks that have been altered by water. They can also occur on steep slopes of highly weathered soil and rocks, such as Paleozoic metamorphic rocks Tertiary volcanic and sedimentary rocks in mountain ranges. The main reason for landslides is heavy rain during the wet season, which tropical cyclones can cause. However, landslides can also be triggered by earthquakes and volcanic eruptions during the dry season (Devoli et al. 2009).

As per the recently published Inform Annual Report for 2021, with a rating between 0 and 10, Nicaragua has been assessed with a medium risk index of 4.6. The country’s vulnerability and exposure have been rated at 5.3, while its vulnerability alone has been marked at 3.5. Additionally, the disasters related to natural hazards index for Nicaragua stands at 6.6, depicting the propensity and exposure of the region to such events. Although there is no exclusive risk index for landslides, floods have been categorized as medium with a score of 5.1 (Table 1) (Inter-Agency Standing Committee and the European Commission 2021

Table 1 Nicaragua risk profile (Source: Inter-Agency Standing Committee and the European Commission 2021)

). Unfortunately, the country’s capacity to recuperate from disasters caused due to tropical cyclones, floods, and landslides has been severely hampered by past disasters like those associated with Hurricane Mitch in 1998 and, more recently, by Eta and Iota in 2020.

According to the most recent statistics available, which date back to 2016, almost a quarter of Nicaragua’s population, specifically 24.9%, lived below the national poverty line (World Bank n.d.). This indicates that a significant portion of the country’s residents could not meet their basic needs and lacked access to crucial resources and opportunities. Thus, they are highly vulnerable and exposed to the impact of landslides and other hazards (Fig. 2).

Fig. 2

Affected people by the impact of Hurricane Felix in Puerto Cabezas, Nicaragua, in 2007 (Source: U.S. Navy photo by Mass Communication Specialist 2nd Class Todd Frantom, Wikimedia Commons)

Economic, social and political instability is a significant obstacle to progressing disaster risk management in Nicaragua. This involves high levels of uncertainty in different aspects, especially concerning the absence of sustained policies. Financial and economic barriers, developing laws and regulation frameworks, lack of capacity building in education and research, professional and technical personnel, insufficiency of relevant land information concerning hazards, vulnerability and exposure, poor environmental data, lack of environmental justice, changings in governments and policies from one government to another, and an atmosphere of conflicts and societal unrest unfold the challenges faced by Nicaraguan people at risk and the diverse governments, at different territorial levels, to mainstreaming disaster risk into development practices.

4 Methodology

In this empirical research study, a desk review was conducted. The search strategy concentrated on prior works that have been central in understanding the spatiotemporal occurrence of tropical storms and rainfall-induced landslides and their impact in Nicaragua. The information was obtained from primary and secondary sources. Original sources included the field recognisance of landslides published in the annual and monthly bulletins of the Nicaraguan Institute of Territorial Studies (INETER), which were used to produce the landslide inventory. Likewise, a desk review was conducted to collect relevant information regarding disaster risk and landslide risk communication from various secondary sources.

After analysing and gathering the information concerning the spatio-temporal occurrence of landslides in Nicaragua for the period 2000–2022, the recorded events were included in a database, which was overlayed on the national geologic map of Nicaragua (Instituto Geográfico Nacional, Servicio Geológico Nacional y Catastro y Recursos Naturales 1974) by using ArcGis 10.5.

5 Results

Rainfall was the main trigger for 51 registered landslides, while only five were associated with earthquakes. Landslide types included lahars, mudflows, debris flows, slides, flows, falls, rotational, shallow, and complex landslides (Table 2, Fig. 3).

Table 2 Spatio-temporal occurrence of rainfall-induced landslides in Nicaragua, 2000–2022

Fig. 3

Landslide inventory of Nicaragua 2000–2022 (Elaborated with information from INETER (n.d.) and Instituto Geográfico Nacional et al. 1974)

The number of registered events per year ranged from 1 to 10, with the highest number of 10 events occurring in 2000. They were categorized according to lithological units, with extrusive volcanic rocks having the highest number of events, with 45. Likewise, 15 Departments, including Carazo, Estelí, León, Jinotega, Región Autónoma de la Costa Caribe Norte, Región Autónoma de la Costa Caribe Sur, Madriz, Boaco, Granada, Managua, Nueva Segovia, Chinandega, Masaya, Matagalpa, and Rivas were affected by landslides. The landslides had an adverse impact on forests, crops, pastures, orchards, water storage facilities, households, roads, highways, schools, churches, power lines, communication poles, and municipal parks.

Due to their dynamic nature and variation in size and location, landslides significantly threaten communities, livelihoods, infrastructure, and the environment. It is imperative to manage risks associated with these hazards from a comprehensive approach. The process entails producing knowledge on disaster risk, which encompasses the identification of hazards, vulnerabilities, exposure, and root causes. This knowledge serves as a foundation for preventing future risk by comprehending the social construction of risk and reducing existing risk through corrective and controlling measures. Additionally, the process encompasses preparing for response and recovering and rebuilding affected areas, including the population’s social, economic, and physical recovery and livelihoods (Narváez et al. 2009) (see Fig. 5).

5.1 Landslide Disaster Risk Communication

Risk communication involves exchanging information and opinions concerning potential risks between individuals, groups, and institutions. This type of communication includes messages that convey the nature of risk and any concerns that may arise in relation to legal and institutional arrangements for risk management arrangements (National Research Council 1989). It is a crucial aspect of risk management that helps to ensure that all stakeholders have a clear understanding of potential risks and the measures that can be taken to mitigate them. Effective risk communication can help minimize the impact of risks and ensure that all parties are well-informed and prepared to deal with any potential issues.

In order to gain a comprehensive understanding of landslides, it is of utmost importance to possess a deep knowledge of both the natural preconditioning factors and the impact of human activities on the stability of the terrain. The destabilization of hillsides can occur due to many aspects, encompassing both naturally occurring and human-induced causes. Identifying the landslide disaster risk drivers is critical to developing effective disaster risk communication and mitigation strategies that can minimize the risks associated with these events.

The Sendai Framework for Disaster Risk Reduction emphasises the need for an integrated understanding of disaster risk. Informed disaster risk management policies and practices necessitate thoroughly comprehending vulnerability, capacity, exposure, hazard characteristics, and the environment. This knowledge can be leveraged for risk assessment prior to disasters, risk prevention and mitigation, and effective preparation and response to disasters. To achieve these objectives, real-time access to dependable data, the utilization of space and in situ information, such as geographic information systems (GIS), and the use of innovative information and communications technology are essential. Effective disaster risk communication is crucial in attaining the necessary understanding (UNISDR 2015).

At the national scale, some institutions and organisations have made considerable efforts to communicate diverse aspects associated with landslide disaster risk. For example, the British Geological Survey involves balancing scientific papers with the public interest. It provides free online resources for obtaining landslide data and an educational resource for all research levels. They also use social media for communication and data collection opportunities (Pennington et al. 2015).

Effective communication for landslide risk should provide all stakeholders with a comprehensive understanding of the potential hazards and factors contributing to vulnerability and exposure. Moreover, it should elucidate the underlying causes and drivers of risk to prevent its transmission to others. By conveying this information clearly and concisely, stakeholders, including laypersons, can make informed decisions and proactively mitigate landslide risks. (Alcántara-Ayala 2018).

One crucial aspect of mitigating the risks associated with landslide disasters is to engage the local community. This can involve several measures, such as building trust, adopting coordinated action strategies, implementing unsafe condition reduction programs, preventing risk exposure, establishing co-responsibility guidelines, and engaging in participatory processes that transcend political and religious affiliations. By implementing these measures, it is possible to manage landslide risk and ensure the safety of communities (Alcántara-Ayala 2018).

Various factors are predicted to increase rainfall-induced landslides, such as population growth, uncontrolled development, and climate change. In Nicaragua, the population experienced a substantial increase of 1.4 million people between 2000 and 2020. Furthermore, the population is expected to grow by 309,454 between 2020 and 2025 (INIDE 2007). Urbanisation in Nicaragua lacks proper territorial management and integrated disaster risk management (Fig. 4). Unfortunately, authorities often overlook the importance of disaster management due to competing priorities. In contrast, the community’s risk perception is frequently shaped by their daily struggles and essential needs. It is vital to prioritize and implement measures to help mitigate the impact of rainfall-induced landslides in Nicaragua, especially through landslide disaster risk communication designed for non-experts. This requires community participation to identify the most appropriate mechanisms to communicate meaningful messages and the best way to implement them according to the living contexts of people at risk, along with previous experience, understanding, priorities and needs.

Fig. 4

Landslides occur frequently in Matagalpa, Nicaragua, due to housing construction on susceptible hillslopes (Source: cgonzalezsoza, Pixabay)

6 Concluding Remarks and Future Steps

It is of utmost importance to enhance the accuracy and precision of data collection about historical and contemporary landslides as it aids in evaluating disaster risks at a national scale. However, it is imperative to note that this data is a foundation for a more thorough and comprehensive assessment, which requires an integrated perspective.

Nicaragua, one of the poorest countries in the Americas, is still struggling with institutional weaknesses that hinder economic and scientific development as it works to recover from dictatorship, civil war, and disasters.

Economic, social, and political instability pose significant obstacles to disaster risk management in Nicaragua. These include policy uncertainty, financial and economic barriers, insufficient capacity building, lack of relevant land information regarding hazards, vulnerability and exposure, poor environmental data, and government changes.

To manage landslide risk, communities must have access to information and knowledge through training, workshops, and public campaigns. This raises awareness and encourages preparedness. Effective landslide disaster risk management includes hazard identification, analysis, strategy development, community participation, and mapping. This is a requisite to creating early warning systems, which are crucial in managing landslide disaster risk from an integrated approach by understanding, addressing, and responding to potential adverse effects, reducing the likelihood of a disaster.

Reviewing the information available regarding the spatio-temporal distribution of recent landslides in Nicaragua provided the possibility to elaborate a landslide inventory at a national scale. This will be used to further construct maps at the Department level that can be incorporated into specific materials for landslide risk communication for laypeople and as a base for organising participatory community workshops. However, it should be noted that the limitations of this work so far include not conducting fieldwork or using satellite images to validate the results. The guidelines of such strategies will consider the key processes of disaster risk management: 1. generating knowledge on disaster risk factors (hazards, vulnerabilities, and exposure); 2. preventing future disaster risk by identifying and addressing the social construction of disaster risk; 3. reducing risk involves implementing corrective and control measures when hazards are known, and effects can be mitigated before they occur; 4. preparing a response plan for disasters; 5. responding, rehabilitating; and 6. recovering and rebuilding affected areas and the population's ways of life. Furthermore, understanding the importance of the drivers of exposure and vulnerability to landslides, along with the meaning of climate change in the intensification of rainfall-induced landslides in Nicaragua, will be at the core of landslide disaster risk communication (Fig. 5). These activities will be undertaken in 2024 at the municipalities most affected by landslides.

Fig. 5

General elements that must be integrated into landslide disaster risk communication strategies (own elaboration)