Comparison of Two Different Earthquake Sources for the 26 December 2004 Aceh Tsunami Simulation

The tsunami wave propagation of the 26 December 2004 Aceh tsunami has been studied by performing a numerical tsunami simulation based on a method that was originally developed by the Tohoku University. The initial model was calculated based on the fault parameters proposed by GFZ Potsdam and Tohoku University. Despite the limitations in the numerical simulation, generally the calculated tsunami heights and arrival times show a relatively good agreement with the observed ones. Based on the simulation it can be estimated that the tsunami wave may reach the west and north coast of northern Sumatra at about 15 to 25 and 20 to 30 minutes after the earthquake, respectively. The maximum calculated tsunami heights in the west and north coast of Aceh were about 11 to 24 and 8 to 15 m, respectively. The calculated arrival times show that the tsunami wave may reach west coast of Thailand and east coast of India and Sri Lanka at about 90 to 100 and 100 to 120 minutes after the earthquake, respectively. The maximum calculated tsunami heights at Phuket of Thailand and Tricomalee of Sri Lanka were about 4 to 5 and 1.5 to 3.5 m, respectively

Prediction of Drought Impact on Rice Paddies in West Java Using Analogue Downscaling Method

Indonesia consistently experiences dry climatic conditions and droughts during El Niño, with significant consequences for rice production. To mitigate the impacts of such droughts, robust, simple and timely rainfall forecast is critically important for predicting drought prior to planting time over rice growing areas in Indonesia. The main objective of this study was to predict drought in rice growing areas using ensemble seasonal prediction. The skill of National Oceanic and Atmospheric Administration's (NOAA's) seasonal prediction model Climate Forecast System version 2 (CFSv2) for predicting rice drought in West Java was investigated in a series of hindcast experiments in 1989-2010. The Constructed Analogue (CA) method was employed to produce downscaled local rainfall prediction with stream function (y) and velocity potential (c) at 850 hPa as predictors and observed rainfall as predictant. We used forty two rain gauges in northern part of West Java in Indramayu, Cirebon, Sumedang and Majalengka Districts. To be able to quantify the uncertainties, a multi-window scheme for predictors was applied to obtain ensemble rainfall prediction. Drought events in dry season planting were predicted by rainfall thresholds. The skill of downscaled rainfall prediction was assessed using Relative Operating Characteristics (ROC) method. Results of the study showed that the skills of the probabilistic seasonal prediction for early detection of rice area drought were found to range from 62% to 82% with an improved lead time of 2-4 months. The lead time of 2-4 months provided sufficient time for practical policy makers, extension workers and farmers to cope with drought by preparing suitable farming practices and equipments

Prediction of Drought Impact on Rice Paddies in West Java Using Analogue Downscaling Method

Indonesia consistently experiences dry climatic conditions and droughts during El Niño, with significant consequences for rice production. To mitigate the impacts of such droughts, robust, simple and timely rainfall forecast is critically important for predicting drought prior to planting time over rice growing areas in Indonesia. The main objective of this study was to predict drought in rice growing areas using ensemble seasonal prediction. The skill of National Oceanic and Atmospheric Administration's (NOAA's) seasonal prediction model Climate Forecast System version 2 (CFSv2) for predicting rice drought in West Java was investigated in a series of hindcast experiments in 1989-2010. The Constructed Analogue (CA) method was employed to produce downscaled local rainfall prediction with stream function (y) and velocity potential (c) at 850 hPa as predictors and observed rainfall as predictant. We used forty two rain gauges in northern part of West Java in Indramayu, Cirebon, Sumedang and Majalengka Districts. To be able to quantify the uncertainties, a multi-window scheme for predictors was applied to obtain ensemble rainfall prediction. Drought events in dry season planting were predicted by rainfall thresholds. The skill of downscaled rainfall prediction was assessed using Relative Operating Characteristics (ROC) method. Results of the study showed that the skills of the probabilistic seasonal prediction for early detection of rice area drought were found to range from 62% to 82% with an improved lead time of 2-4 months. The lead time of 2-4 months provided sufficient time for practical policy makers, extension workers and farmers to cope with drought by preparing suitable farming practices and equipments

Delineation of Upper Crustal Structure Beneath the Island of Lombok, Indonesia, Using Ambient Seismic Noise Tomography

We have successfully conducted the first ambient noise tomography on the island of Lombok, Indonesia using local waveform data observed at 20 temporary stations. Ambient noise tomography was used to delineate the seismic velocity structure in the upper crust. The waveform data were recorded from August 3rd to September 9th, 2018, using short-period and broadband sensors. There are 185 Rayleigh waves retrieved from cross-correlating the vertical components of the seismograms. We used frequency-time analysis (FTAN) to acquire the interstation group velocity from the dispersion curves. Group velocity was obtained for the period range of 1 s to 6 s. The group velocity maps were generated using the subspace inversion method and Fast Marching Method (FMM) to trace ray-paths of the surface waves through a heterogeneous medium. To extract the shear wave velocity (Vs) from the Rayleigh wave group velocity maps, we utilize the Neighborhood Algorithm (NA) method. The 2-D tomographic maps provide good resolution in the center and eastern parts of Lombok. The tomograms show prominent features with a low shear velocity that appears up to 4 km depth beneath Rinjani Volcano, Northern Lombok, and Eastern Lombok. We suggest these low velocity anomalies are associated with Quaternary volcanic products, including the Holocene pyroclastic deposits of Samalas Volcano (the ancient Rinjani Volcano) which erupted in 1257. The northeast of Rinjani Volcano is characterized by higher Vs, and we suggest this may be due to the presence of igneous intrusive rock at depth

P and S velocity sturcture of the crust and the upper mantle beneath Central Java from local tomography inversion

Here we present the results of local source tomographic inversion beneath central Java. The data set was collected by a temporary seismic network. More than 100 stations were operated for almost half a year. About 13,000 P and S arrival times from 292 events were used to obtain three-dimensional (3-D) Vp, Vs, and Vp/Vs models of the crust and the mantle wedge beneath central Java. Source location and determination of the 3-D velocity models were performed simultaneously based on a new iterative tomographic algorithm, LOTOS-06. Final event locations clearly image the shape of the subduction zone beneath central Java. The dipping angle of the slab increases gradually from almost horizontal to about 70°. A double seismic zone is observed in the slab between 80 and 150 km depth. The most striking feature of the resulting P and S models is a pronounced low-velocity anomaly in the crust, just north of the volcanic arc (Merapi-Lawu anomaly (MLA)). An algorithm for estimation of the amplitude value, which is presented in the paper, shows that the difference between the fore arc and MLA velocities at a depth of 10 km reaches 30% and 36% in P and S models, respectively. The value of the Vp/Vs ratio inside the MLA is more than 1.9. This shows a probable high content of fluids and partial melts within the crust. In the upper mantle we observe an inclined low-velocity anomaly which links the cluster of seismicity at 100 km depth with MLA. This anomaly might reflect ascending paths of fluids released from the slab. The reliability of all these patterns was tested thoroughly

Processing and Preparation of Brassica Vegetables and the Fate of Glucosinolates

The healthiness of a vegetable cannot solely be inferred from the amount ofhealth-promoting compounds in the raw materials. Brassica vegetables, forexample, are consumed mostly after processing to improve palatability and toextend the shelf life. However, processing also results to various changes in thecontent of glucosinolates which intakes are associated with a reduced risk ofseveral cancers. The large variety in cooking practices and processing methods affect the glucosinolate content in the vegetables, particularly due to processes that allow for enzymatic hydrolysis and thermal degradation of glucosinolates, and leaching of the bioactive components. Knowledge on the effect of preparation and processing of Brassica vegetables is important to evaluate the healthiness of the consumed product and to investigate mechanisms to retain high glucosinolate levels at the stage of consumption and to increase the intake of health-protective compounds by the consumer. By using a mechanistic approach, the fate of glucosinolates during different processing and preparation methods and conditions can be explained. Boiling and blanching reduce the glucosinolate content significantly particularly because of the mechanisms of leaching following cell lysis and diffusion, and partly due to thermal and enzymatic degradation. Steaming, microwave processing, and stir frying either retain or only slightly reduce the glucosinolate content due to low degrees of leaching. These methods can enhance the accessibility of glucosinolates from the plant tissue. Fermentation reduces the glucosinolate content considerably, the underlying mechanisms are not yet completely clear, but enzymatic breakdown seems to play an important role. Studying the changes of glucosinolates during processing by a mechanistic approach is shown to be valuable to redesign the processing and to reformulate the product for improving health benefits of these compounds