scholarly journals New Insight into Post-seismic Landslide Evolution Processes in the Tropics

2021 ◽  
Vol 9 ◽  
Author(s):  
Hakan Tanyaş ◽  
Dalia Kirschbaum ◽  
Tolga Görüm ◽  
Cees J. van Westen ◽  
Luigi Lombardo
Keyword(s):  
Landslide Susceptibility ◽  
Precipitation Regime ◽  
Entire Area ◽  
Tropical Conditions ◽  
Multi Temporal ◽  
Landslide Evolution ◽  
Landslide Processes ◽  
Seismic Landslide ◽  
External Forces ◽  
The Tropics

Earthquakes do not only trigger landslides in co-seismic phases but also elevate post-seismic landslide susceptibility either by causing a strength reduction in hillslope materials or by producing co-seismic landslide deposits, which are prone to further remobilization under the external forces generated by subsequent rainfall events. However, we still have limited observations regarding the post-seismic landslide processes. And, the examined cases are rarely representative of tropical conditions where the precipitation regime is strong and persistent. Therefore, in this study, we introduce three new sets of multi-temporal landslide inventories associated with subsets of the areas affected by 1) 2016 Reuleuet (Indonesia, Mw = 6.5), 2) 2018 Porgera (Papua New Guinea, Mw = 7.5) and 3) 2012 Sulawesi (Indonesia, Mw = 6.3), 2017 Kasiguncu (Indonesia, Mw = 6.6) and 2018 Palu (Indonesia, Mw = 7.5) earthquakes. Overall, our findings show that the landslide susceptibility level associated with the occurrences of new landslides return to pre-seismic conditions in less than a year in the study areas under consideration. We stress that these observations might not be representative of the entire area affected by these earthquakes but the areal boundaries of our study areas.

scholarly journals New insight into post-seismic landslide evolution processes in the tropics

2021 ◽  
Author(s):  
Hakan Tanyas ◽  
Dalia Kirschbaum ◽  
Tolga Gorum ◽  
Cees van Westen ◽  
Luigi Lombardo
Keyword(s):  
Landslide Evolution ◽  
Seismic Landslide ◽  
The Tropics ◽  
Insight Into

A simple design and operation for the anaerobic treatment of highly concentrated swine waste in the tropics

1995 ◽  
Vol 32 (12) ◽  
pp. 91-97 ◽  
Author(s):  
P. Y. Yang ◽  
M. Kuroshima
Keyword(s):  
Treatment Process ◽  
Total Solid ◽  
Anaerobic Treatment ◽  
Solid Content ◽  
Total Solid Content ◽  
Treatment Processes ◽  
Tropical Conditions ◽  
Biological Reaction ◽  
The Tropics ◽  
Small Producers

In order to develop a simple operation for an anaerobic treatment process for highly concentrated pig wastewater for small producers, a three-stage anaerobic treatment process was investigated. The system provided a series of mixing, homogenization, biological reaction and final stabilization of concentrated pig waste (total solid content of 8–10%). The process provided a stable operational performance, simple operational procedure and well stabilized sludge effluent. It was also found that the system is economically feasible in Hawaii. Compared to the other treatment processes for highly concentrated pig waste, this process is considered as an appropriate alternative for the application of the small producers in land limited and tropical conditions. Also, the present treatment system can be easily developed into a prefabricated package plant which can minimize the on-site labor and building costs.

scholarly journals Three exceptionally strong East-Asian summer monsoon events during glacial conditions in the past 470 kyr

2008 ◽  
Vol 4 (6) ◽  
pp. 1289-1317 ◽  
Author(s):  
D.-D. Rousseau ◽  
N. Wu ◽  
Y. Pei ◽  
F. Li
Keyword(s):  
Summer Monsoon ◽  
Asian Monsoon ◽  
East Asian Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Precipitation Regime ◽  
The Past ◽  
Ecological Requirements ◽  
Asian Summer ◽  
The Tropics

Abstract. Chinese loess sequences are interpreted as a reliable record of the past variation of the East Asian monsoon regime through the alternation of loess and paleosols units, dominated by the winter and summer monsoon, respectively. Different proxies have been used to describe this system, mostly geophysical, geochemical or sedimentological. Terrestrial mollusks are also a reliable proxy of past environmental conditions and are often preserved in large numbers in loess deposits. The analysis of the mollusk remains in the Luochuan sequence, comprising L5 loess to S0 soil, i.e. the last 500 ka, shows that for almost all identified species, the abundance is higher at the base of the interval (L5 to L4) than in the younger deposits. Using the present ecological requirements of the identified mollusk species in the Luochuan sequence allows the definition of two main mollusk groups varying during the last 500 kyr. The cold-aridiphilous individuals indicate the so-called Asian winter monsoon regime and predominantly occur during glacials, when dust is deposited. The thermal-humidiphilous mollusks are prevalent during interglacial or interstadial conditions of the Asian summer monsoon, when soil formation takes place. In the sequence, three events with exceptionally high abundance of the Asian summer monsoon indicators are recorded during the L5, L4 and L2 glacial intervals, i.e., at about 470, 360 and 170 kyr, respectively. The L5 and L4 events appear to be the strongest (high counts). Similar variations have also been identified in the Xifeng sequence, distant enough from Luochuan, but also in Lake Baikal further North, to suggest that this phenomenon is regional rather than local. The indicators of the summer monsoon within the glacial intervals imply a strengthened East-Asian monsoon interpreted as corresponding to marine isotope stages 6, 10 and 12, respectively. The L5 and L2 summer monsoons are coeval with Mediterranean sapropels S12 and S6, which characterize a strong African summer monsoon with relatively low surface water salinity in the Indian Ocean. Changes in the precipitation regime could correspond to a response to a particular astronomical configuration (low obliquity, low precession, summer solstice at perihelion) leading to an increased summer insolation gradient between the tropics and the high latitudes and resulting in enhanced atmospheric water transport from the tropics to the African and Asian continents. However, other climate drivers such as reorganization of marine and atmospheric circulations, tectonic, and the extent of the Northern Hemisphere ice sheet are also discussed.

The use of diets containing high levels of copra meal for growing/finishing pigs

1997 ◽  
Vol 1987 ◽  
pp. 97-97
Author(s):  
P.J. Thorne ◽  
J. Wiseman ◽  
D.J.A. Cole
Keyword(s):  
Coconut Oil ◽  
Oil Industry ◽  
The Philippines ◽  
Finishing Pigs ◽  
Poor Growth ◽  
Copra Meal ◽  
Potential Source ◽  
Tropical Conditions ◽  
The University ◽  
The Tropics

Copra meal is a by-product of the coconut oil industry and is a potential source of protein and energy in the diets of pigs and poultry in the tropics. However, previous studies with pigs have suggested that its use may be limited because of poor growth performance associated with levels of inclusion above 300 g/kg (Creswell and Brooks, 1971). The experiment reported here and conducted under tropical conditions at the University of the Philippines at Los Banos was designed to study possible ways of feeding copra meal at levels of inclusion greater than 300 g/kg in the diets of pigs while maintaining acceptable animal performance.

Effect of dietary energy intake during pregnancy on liveweight gain and backfat gain of primiparous sows kept in an outdoor system under tropical conditions

2000 ◽  
Vol 2000 ◽  
pp. 107-107
Author(s):  
R. H. Santos Ricalde ◽  
I. J. Lean
Keyword(s):  
Energy Level ◽  
Energy Intake ◽  
Energy Requirements ◽  
Dietary Energy ◽  
Feeding Management ◽  
Dietary Energy Intake ◽  
Tropical Environments ◽  
Tropical Conditions ◽  
Feeding Resources ◽  
The Tropics

Energy requirements for maintenance in pregnant sows increase when they are kept outdoors under temperate climates in comparison to indoors. However, there is little information on the energy requirements of breeding sows kept outdoors in tropical environments. Knowledge about the correct feeding management for pregnant sows kept outdoors will optimise the utilisation of feeding resources available in the tropics. The aim of this study was to evaluate the effect of energy level supply during pregnancy on backfat change and liveweight change of primiparous sows kept outdoors under tropical conditions.

scholarly journals Landslide Susceptibility Based on Extreme Rainfall-Induced Landslide Inventories and the Following Landslide Evolution

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2609 ◽  
Author(s):  
Chunhung Wu
Keyword(s):  
Landslide Susceptibility ◽  
Extreme Rainfall ◽  
Susceptibility Map ◽  
Typhoon Morakot ◽  
Landslide Susceptibility Map ◽  
Related Factors ◽  
Extreme Rainfall Events ◽  
River Watershed ◽  
Correct Ratio ◽  
Landslide Evolution

Landslide susceptibility assessment is crucial for mitigating and preventing landslide disasters. Most landslide susceptibility studies have focused on creating landslide susceptibility models for specific rainfall or earthquake events, but landslide susceptibility in the years after specific events are also valuable for further discussion, especially after extreme rainfall events. This research provides a new method to draw an annual landslide susceptibility map in the 5 years after Typhoon Morakot (2009) in the Chishan River watershed in Taiwan. This research establishes four landslide susceptibility models by using four methods and 12 landslide-related factors and selects the model with the optimum performance. This research analyzes landslide evolution in the 5 years after Typhoon Morakot and estimates the average landslide area different ratio (LAD) in upstream, midstream, and downstream of the Chishan River watershed. We combine landslide susceptibility with the model with the highest performance and average annual LAD to draw an annual landslide susceptibility map, and its mean correct ratio ranges from 62.5% to 73.8%.

scholarly journals Comparison of Random Forest Model and Frequency Ratio Model for Landslide Susceptibility Mapping (LSM) in Yunyang County (Chongqing, China)

2020 ◽  
Vol 17 (12) ◽  
pp. 4206 ◽  
Author(s):  
Yue Wang ◽  
Deliang Sun ◽  
Haijia Wen ◽  
Hong Zhang ◽  
Fengtai Zhang
Keyword(s):  
Random Forest ◽  
Landslide Susceptibility ◽  
Frequency Ratio ◽  
Coincidence Degree ◽  
Susceptibility Mapping ◽  
Machine Learning Techniques ◽  
Landslide Susceptibility Mapping ◽  
Training Dataset ◽  
Entire Area ◽  
Conditioning Factors

To compare the random forest (RF) model and the frequency ratio (FR) model for landslide susceptibility mapping (LSM), this research selected Yunyang Country as the study area for its frequent natural disasters; especially landslides. A landslide inventory was built by historical records; satellite images; and extensive field surveys. Subsequently; a geospatial database was established based on 987 historical landslides in the study area. Then; all the landslides were randomly divided into two datasets: 70% of them were used as the training dataset and 30% as the test dataset. Furthermore; under five primary conditioning factors (i.e., topography factors; geological factors; environmental factors; human engineering activities; and triggering factors), 22 secondary conditioning factors were selected to form an evaluation factor library for analyzing the landslide susceptibility. On this basis; the RF model training and the FR model mathematical analysis were performed; and the established models were used for the landslide susceptibility simulation in the entire area of Yunyang County. Next; based on the analysis results; the susceptibility maps were divided into five classes: very low; low; medium; high; and very high. In addition; the importance of conditioning factors was ranked and the influence of landslides was explored by using the RF model. The area under the curve (AUC) value of receiver operating characteristic (ROC) curve; precision; accuracy; and recall ratio were used to analyze the predictive ability of the above two LSM models. The results indicated a difference in the performances between the two models. The RF model (AUC = 0.988) performed better than the FR model (AUC = 0.716). Moreover; compared with the FR model; the RF model showed a higher coincidence degree between the areas in the high and the very low susceptibility classes; on the one hand; and the geographical spatial distribution of historical landslides; on the other hand. Therefore; it was concluded that the RF model was more suitable for landslide susceptibility evaluation in Yunyang County; because of its significant model performance; reliability; and stability. The outcome also provided a theoretical basis for application of machine learning techniques (e.g., RF) in landslide prevention; mitigation; and urban planning; so as to deliver an adequate response to the increasing demand for effective and low-cost tools in landslide susceptibility assessments.

scholarly journals Seasonal Differences in Animal Welfare Assessment of Family Farming Dual-Purpose Cattle Raised under Tropical Conditions

Animals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 125
Author(s):  
Adalinda Hernandez ◽  
Charlotte Berg ◽  
Rebecka Westin ◽  
Carlos Galina
Keyword(s):  
Animal Welfare ◽  
Rainy Season ◽  
Dry Season ◽  
Family Farms ◽  
Family Farming ◽  
Dual Purpose ◽  
Tropical Conditions ◽  
Dual Purpose Cattle ◽  
The Tropics ◽  
Mexican Tropics

Conditions on farms in the tropics can differ greatly depending on the season of the year. Characteristics such as disease prevalence, climate and availability of resources may not be constant all year around; however an acceptable level of animal welfare must be maintained throughout the year. Since it is neither practical nor economically feasible to perform several assessments per year, the purpose of this study was to define whether there were animal welfare issues at farms that were affected by the season to identify which season would present a greater risk to animal welfare, using a risk-based approach. Forty-five dual-purpose family farms in the Mexican tropics were assessed via the Welfare Quality® protocol. During the rainy season, 2.2% of the farms were classified as excellent, 57.8% as enhanced, 31.1% as acceptable and 8.9% as unclassified. In the dry season, 31.1% were classified as excellent, 68.9% as enhanced and none of the farms were categorized as acceptable or unclassified. Consequently, the season which presented the greatest risk to animal welfare of dual-purpose cattle raised under tropical conditions was the rainy season. However, there were management-related differences observed between the two seasons and the dry season also had some animal welfare threats. The fact that farms scored higher during the dry season is possibly the result of farmer awareness, leading to modification of their systems to provide animals with the necessary inputs to meet their production needs. If these modifications were not fulfilled, then welfare conditions might have been jeopardized.

Seasonal variation in some characteristics of seminal plasma of Sudan Desert sheep in the tropics

1982 ◽  
Vol 99 (1) ◽  
pp. 45-49 ◽  
Author(s):  
K. A. A. Galil ◽  
A. K. A. Galil
Keyword(s):  
Seasonal Variation ◽  
Seminal Plasma ◽  
Rainy Season ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Monthly Variation ◽  
Hydrogen Ion Concentration ◽  
Tropical Conditions ◽  
Hot Weather ◽  
The Tropics

SUMMARYSome androgen-dependent constituents of seminal plasma of Sudan Desert rams were measured during the hot dry summer, the hot rainy season and the winter under tropical conditions in the Sudan. Higher concentrations of both fructose and citric acid were obtained between July and October during the rainy season and low values between January and April during winter, with marked monthly and seasonal variation in both characters. Considerable monthly variation in the hydrogen-ion concentration of semen was obtained with lower values between August and January and higher values between February and July. The androgenic status of the animals appears not to be decreased during the hot weather, but no explanation can be offered for the decrease during the winter.

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