Method for Real-Time Evaluation of Discharge Rate of Volcanic Ash – Case Study on Intermittent Eruptions at the Sakurajima Volcano, Japan –

2016 ◽  
Vol 11 (1) ◽  
pp. 4-14 ◽  
Author(s):  
Masato Iguchi ◽  
Keyword(s):  
Linear Combination ◽  
Real Time ◽  
Volcanic Ash ◽  
Ground Deformation ◽  
Discharge Rate ◽  
Sakurajima Volcano ◽  
Seismic Amplitude ◽  
Ash Weight ◽  
Better Than

A method for evaluating the volcanic ash discharge rate by using seismic and ground deformation signals is proposed to obtain this rate in real time for southern Kyushu’s Sakurajima volcano. This volcano repeats vulcanian eruptions accompanying significant ground deformation showing deflation and nonvulcanian type eruptions that emit the minor emissions of volcanic ash associated with volcanic tremors but without significant ground deformation. We examined ground deformation and seismic amplitude as they relate to monthly sums of volcanic ash weight ejected from craters. We found that in monthly sums, both deflation ground deformation and the amplitude of volcanic tremors correlate positively with the weight of ejected volcanic ash. A linear combination of terms for ground deformation, seismic amplitude and a correction factor correlates better than single parameter of deflation or seismic amplitude with volcanic ash weight. The linear combination provides the volcanic ash discharge rate in quasi-real time and the total amount of volcanic ash distributed over a wide area immediately after a volcanic eruption ends.

Integrated Monitoring of Volcanic Ash and Forecasting at Sakurajima Volcano, Japan

2019 ◽  
Vol 14 (5) ◽  
pp. 798-809 ◽  
Author(s):  
Masato Iguchi ◽  
Haruhisa Nakamichi ◽  
Hiroshi Tanaka ◽  
Yusaku Ohta ◽  
Atsushi Shimizu ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Ground Deformation ◽  
Discharge Rate ◽  
Seismic Energy ◽  
Deformation Monitoring ◽  
Volcanic Plume ◽  
Fall Deposit ◽  
Integrated Monitoring ◽  
Sakurajima Volcano ◽  
Ash Fall

The Sakurajima volcano is characterized by frequent vulcanian eruptions at the Minamidake or Showa crater in the summit area. We installed an integrated monitoring system for the detection of volcanic ash (composed of remote sensing sensors XMP radars, lidar, and GNSS with different wave lengths) and 13 optical disdrometers on the ground covering all directions from the crater to measure drop size distribution and falling velocity. Campaign sampling of volcanic ash supports the conversion of particle counts measured by the disdrometer to the weight of volcanic ash. Seismometers and tilt/strain sensors were used to estimate the discharge rate of volcanic ash from the vents. XMP radar can detect volcanic ash clouds even under visual difficulty because of weather such as fog or clouds. A vulcanian eruption on November 13 was the largest event at the Sakurajima volcano in 2017; however, the volcanic plume was not visible due to clouds covering the summit. Radar revealed that the volcanic plume reached an elevation of 4.2–6.2 km. Post-fit phase residuals (PPR) from the GNSS analysis increased suddenly after the eruption, and large-PPR paths from the satellites to the ground-based receivers intersected each other at an elevation of 4.2 km. The height of the volcanic plume was also estimated from the discharge rate of volcanic ash to be 4.5 km, which is empirically related to seismic energy and the deflation volume obtained via ground deformation monitoring. Using the PUFF model, the weight of the ash-fall deposit was accurately forecast in the main direction of transport of the volcanic ash, which was verified by disdrometers. For further advances in forecasting of the ash-fall deposit, we must consider high-resolution wind field, shape of volcanic plume as the initial value, and the particle number distribution along the volcanic plume.

Integrated Study on Forecasting Volcanic Hazards of Sakurajima Volcano, Japan

2020 ◽  
Vol 15 (2) ◽  
pp. 174-186
Author(s):  
Masato Iguchi ◽  
◽  
Haruhisa Nakamichi ◽  
Takeshi Tameguri
Keyword(s):  
Volcanic Ash ◽  
Discharge Rate ◽  
Seismic Energy ◽  
Pyroclastic Flows ◽  
Occurrence Rate ◽  
Magma Intrusion ◽  
Integrated Monitoring ◽  
Summit Eruption ◽  
Volcanic Earthquakes ◽  
Sakurajima Volcano

Several types of eruptions have occurred at Sakurajima volcano in the past 100 years. The eruption in 1914 was of a Plinian type followed by an effusion of lava. The progression of seismicity of volcanic earthquakes prior to the eruption is reexamined and seismic energy is estimated to be an order of 1014 J. Lava also effused from the Showa crater in 1946. Since 1955, eruptions frequently have occurred at the Minamidake or Showa craters at the summit area. Vulcanian eruptions are a well-known type of summit eruption of Sakurajima, however Strombolian type eruptions and continuous ash emissions have also occurred at the Minamidake crater. The occurrence rate of pyroclastic flows significantly increased during the eruptivity of Showa crater, with the occurrence of lava fountains. Tilt and strain observations are reliable tools to forecast the eruptions, and their combination with the seismicity of volcanic earthquakes is applicable to forecasting the occurrence of pyroclastic flows. An empirical event branch logic based on magma intrusion rate is proposed to forecast the scale and type of eruption. Forecasting the scale of an eruption and real-time estimations of the discharge rate of volcanic ash allows us to assess ash fall deposition around the volcano. Volcanic ash estimation is confirmed by an integrated monitoring system of X Band Multi-Parameter radars, lidar and the Global Navigation Satellite System to detect volcanic ash particles with different wave lengths. Evaluation of the imminence of eruptions and forecasting of their scale are used for the improvement of planning and drilling of volcanic disaster measures.

scholarly journals Numerical Simulations of Volcanic Ash Plume Dispersal for Sakura-Jima Using Real-Time Emission Rate Estimation

2019 ◽  
Vol 14 (1) ◽  
pp. 160-172 ◽  
Author(s):  
Hiroshi L. Tanaka ◽  
Masato Iguchi ◽  
◽  
Keyword(s):  
Real Time ◽  
Volcanic Ash ◽  
Emission Rate ◽  
Ground Deformation ◽  
Dispersion Model ◽  
Model Performance ◽  
Danger Zone ◽  
Rate Estimation ◽  
Ash Dispersion ◽  
Ash Fallout

In this study, a real-time volcanic ash dispersion model called PUFF is applied to the Sakura-jima volcano erupted on 16 June 2018 to assess the performance of the new system connected with a real-time emission rate estimation. The emission rate of the ash mass from the vent is estimated based on an empirical formula developed for the Sakura-jima volcano using seismic monitoring and ground deformation data. According to the time series of the estimated emission rate, a major eruption occurred at 7:20 JST indicating an emission rate of 1000 t/min and continued for 15 min showing a plume height of 4500 m. It is observed that we need to introduce an adjusting constant to fit the model prediction of the ash fallout with the ground observation. Once the particle mass is calibrated, the distributions of ash fallout are compared with other eruption events to confirm the model performance. According to the PUFF model simulations, an airborne ash concentration of 100 mg/m3extends to a wide area around the volcano within one hour after the eruption. The simulation result quantitatively indicates the location of the danger zone for commercial airliners. The PUFF model system combined with the real-time emission rate estimation is useful for aviation safety purposes as well as for ground transportation and human health around active volcanoes.

scholarly journals PUFF Model Prediction of Volcanic Ash Plume Dispersal for Sakurajima Using MP Radar Observation

Atmosphere ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1240
Author(s):  
Hiroshi L. Tanaka ◽  
Haruhisa Nakamichi ◽  
Masato Iguchi
Keyword(s):  
Real Time ◽  
Direct Observation ◽  
Model Prediction ◽  
Volcanic Ash ◽  
Radar Data ◽  
Radar Observation ◽  
Japan Meteorological Agency ◽  
Plume Height ◽  
Sakurajima Volcano ◽  
Ash Plume

In this study, a real-time volcanic ash plume prediction by the PUFF system was applied to the Sakurajima volcano (which erupted at 17:24 Japan Standard Time (JST) on 8 November 2019), using the direct observation of the multi-parameter (MP) radar data installed at the Sakurajima Volcano Research Center. The MP radar showed a plume height of 5500 m a.s.l. around the volcano. The height was higher than the 4000 m by the PUFF system, but was lower than the observational report of 6500 m by the Japan Meteorological Agency in Kagoshima. In this study, ash particles by the MP radar observation were assimilated to the running PUFF system operated by the real-time emission rate and plume height, since the radar provides accurate plume height. According to the simulation results, the model prediction has been improved in the shape of the ash cloud with accurate plume top by the new MP radar observation. The plume top is corrected from 4000 m to 5500 m a.s.l., and the three-dimensional (3D) ash dispersal agrees with the observation. It was demonstrated by this study that the direct observation of MP radar obviously improved the model prediction, and enhanced the reliability of the prediction model.

Pollution based real time control strategies for combined sewer systems

1997 ◽  
Vol 36 (8-9) ◽  
pp. 331-336 ◽  
Author(s):  
Gabriela Weinreich ◽  
Wolfgang Schilling ◽  
Ane Birkely ◽  
Tallak Moland
Keyword(s):  
Real Time ◽  
Control Strategies ◽  
Ammonia Nitrogen ◽  
Simple Extension ◽  
Real Time Control ◽  
Time Control ◽  
Sewer Systems ◽  
Receiving Waters ◽  
Tunnel System

This paper presents results from an application of a newly developed simulation tool for pollution based real time control (PBRTC) of urban drainage systems. The Oslo interceptor tunnel is used as a case study. The paper focuses on the reduction of total phosphorus Ptot and ammonia-nitrogen NH4-N overflow loads into the receiving waters by means of optimized operation of the tunnel system. With PBRTC the total reduction of the Ptot load is 48% and of the NH4-N load 51%. Compared to the volume based RTC scenario the reductions are 11% and 15%, respectively. These further reductions could be achieved with a relatively simple extension of the operation strategy.

Municipal wastewater treatment with pond–constructed wetland system: a case study

2005 ◽  
Vol 51 (12) ◽  
pp. 325-329 ◽  
Author(s):  
X. Wang ◽  
X. Bai ◽  
J. Qiu ◽  
B. Wang
Keyword(s):  
Constructed Wetland ◽  
Municipal Wastewater ◽  
Municipal Wastewater Treatment ◽  
Oxidation Pond ◽  
System A ◽  
Treated Effluent ◽  
Wetland System ◽  
Oxidation Ponds ◽  
Better Than

The performance of a pond–constructed wetland system in the treatment of municipal wastewater in Kiaochow city was studied; and comparison with oxidation ponds system was conducted. In the post-constructed wetland, the removal of COD, TN and TP is 24%, 58.5% and 24.8% respectively. The treated effluent from the constructed wetland can meet the Chinese National Agricultural and Irrigation Standard. The comparison between pond–constructed wetland system and oxidation pond system shows that total nitrogen removal in a constructed wetland is better than that in an oxidation pond and the TP removal is inferior. A possible reason is the low dissolved oxygen concentration in the wetland. Constructed wetlands can restrain the growth of algae effectively, and can produce obvious ecological and economical benefits.

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