Geochronology,Eruption Sequence and Geochemistry of Mid-Late Jurassic Volcanics South of Manzhouli:Petrogenesis and Implications for Mesozoic Tectonic Regime Transformation

To the south of Manzhouli,Hulunbuir,Inner Mongolia,experienced a tectonic regime transformation from compression to extension in the mid-Mesozoic.Based on systematic research of the volcanics,petrology,volcanic facies,chronology and geochemistry of rocks in the Buridun area,two stages of volcanics are identified.The first stage named the trachyte series was formed in the late Middle Jurassic(167-163 Ma),its eruption rhythm is pyroxene trachyandesite-trachyandesite-trachyte,and its origin rock is basic volcanics from thickened lower crust,with a tectonic setting in the collision orogeny after the closure of the Mongolia Okhotsk Ocean(MOO).The second stage is a bimodal volcanic rock,formed in the early Late Jurassic(163-160 Ma).The eruption rhythm of basic volcanics in this stage is basaltic andesite-basalt-olivine basalt,which comes from the metasomatized lithospheric mantle,the acidic volcanics of which being characterized by the eruption rhythm of sedimentary-explosive-overflow facies,which came from the partial melting of newly formed lower crust,and this shows the characteristics of A-type granite;the tectonic setting is extension of the lithosphere after collision and closure of the MOO.The changes in the formation age and tectonic setting of the two stages of volcanics demonstrate that the transition time from the compressive system to the extensional system south of Manzhouli is about 163 Ma.

Subaqueous volcanic eruptive facies,facies model and its reservoir significance in a continental lacustrine basin:A case from the Cretaceous in Chaganhua area of southern Songliao Basin,NE China

The conventional lithofacies and facies model of subaerial and marine pyroclastic rocks cannot reflect the characteristics of subaqueous volcanic edifice in lacustrine basins.In order to solve this problem,the lithofacies of subaqueous eruptive pyroclastic rocks is discussed and the facies model is established by taking the tuff cone of Cretaceous Huoshiling Formation in the Chaganhua area of the Changling fault depression,Songliao Basin as the research object.The results indicate that the subaqueous eruptive pyroclastic rocks in the Songliao Basin can be divided into two facies and four subfacies.The two facies are the subaqueous explosive facies and the volcanic sedimentary facies that is formed during the eruption interval.The subaqueous explosive facies can be further divided into three subfacies:gas-supported hot pyroclastic flow subfacies,water-laid density current subfacies and subaqueous fallout subfacies.The volcanic sedimentary facies consists of pyroclastic sedimentary rocks containing terrigenous clast subfacies.A typical facies model of the tuff cone that is formed by subaqueous eruptions in the Songliao Basin was established.The tuff cone is generally composed of multiple subaqueous eruption depositional units and can be divided into two facies associations:near-source facies association and far-source facies association.The complete vertical succession of one depositional unit of the near-source facies association is composed of pyroclastic sedimentary rocks containing terrigenous clast subfacies,gas-supported hot pyroclastic flow subfacies,water-laid density current subfacies and subaqueous fallout subfacies from bottom to top.The depositional unit of the far-source facies association is dominated by the subaqueous fallout subfacies and contains several thin interlayered deposits of the water-laid density current subfacies.The gas-supported hot pyroclastic flow subfacies and the pyroclastic sedimentary rocks containing terrigenous clast subfacies are favorable subaqueous eruptive facies for reservoirs in continental lacustrine basins.

Relationship between earthquake and volcanic eruption inferred from historical records

史料记载表明，五大连池火山1720～1721年喷发期间有大量地震活动．本文从描述这些地震活动的文字记录人手，并结合国际火山地震研究的新成果，探讨了地震类型及地震与火山喷发关系，指出震群是火山喷发的重要前兆指标，强调火山地震的监测对火山喷发预报的意义．

The Effect of Super Volcanic Eruptions on Ozone Depletion in a Chemistry–Climate Model

With the gradual yet unequivocal phasing out of ozone depleting substances(ODSs), the environmental crisis caused by the discovery of an ozone hole over the Antarctic has lessened in severity and a promising recovery of the ozone layer is predicted in this century. However, strong volcanic activity can also cause ozone depletion that might be severe enough to threaten the existence of life on Earth. In this study, a transport model and a coupled chemistry–climate model were used to simulate the impacts of super volcanoes on ozone depletion. The volcanic eruptions in the experiments were the 1991 Mount Pinatubo eruption and a 100 × Pinatubo size eruption. The results show that the percentage of global mean total column ozone depletion in the 2050 RCP8.5 100 × Pinatubo scenario is approximately 6% compared to two years before the eruption and 6.4% in tropics. An identical simulation, 100 × Pinatubo eruption only with natural source ODSs, produces an ozone depletion of 2.5% compared to two years before the eruption, and with 4.4% loss in the tropics. Based on the model results,the reduced ODSs and stratospheric cooling lighten the ozone depletion after super volcanic eruption.

The Response of the East Asian Summer Monsoon to Strong Tropical Volcanic Eruptions

A 600-year integration performed with the Bergen Climate Model and National Centers for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR） reanalysis data were used to investigate the impact of strong tropical volcanic eruptions on the East Asian summer monsoon （EASM） and EASM rainfall.Both the simulation and NCEP/NCAR reanalysis data show a weakening of the EASM in strong eruption years.The model simulation suggests that North and South China experience droughts and the Yangtze-Huaihe River Valley experiences floods during eruption years.In response to strong tropical volcanic eruptions,the meridional air temperature gradient in the upper troposphere is enhanced,which leads to a southward shift and an increase of the East Asian subtropical westerly jet stream （EASWJ）.At the same time,the land-sea thermal contrast between the Asian land mass and Northwest Pacific Ocean is weakened.The southward shift and increase of the EASWJ and reduction of the land-sea thermal contrast all contribute to a weakening of the EASM and EASM rainfall anomaly.

Filling Pattern of Volcanostratigraphy of Cenozoic Volcanic Rocks in the Changbaishan Area and Possible Future Eruptions

The Cenozoic volcanostratigraphy in the Changbaishan area had complex building processes.Twenty-two eruption periods have been determined from the Wangtian＇e, Touxi, and Changbaishan volcanoes. The complex volcanostratigraphy of the Changbaishan area can be divided into four types of filling patterns from bottom to top. They are lava flows filling in valleys（LFFV）, lava flows filling in platform（LFFP）, lava flows formed the cone（LFFC）, and pyroclastic Flow filling in crater or valleys（PFFC/V）. LFFV has been divided into four layers and terminates as a lateral overlap. The topography of LFFV, which is controlled by the landform, is lens shaped with a wide flat top and narrow bottom.LFFP has been divided into three layers and terminates as a lateral downlap. The topography of LFFP is sheet and tabular shaped with a narrow top and wide bottom. It has large width to thickness ratio. It was built by multiple eruptive centers distributed along the fissure. The topography of LFFC, which is located above the LFFP, has a hummocky shape with a narrow sloping top and a wide flat bottom. It terminates as a later downlap or backstepping. It has large width to thickness ratio. It was built by a single eruptive center. The topography of PFFC/V, which located above the LFFC, LFFP, or valley, has the shape of fan and terminates as a lateral downlap or overlap. It has a small width to thickness ratio and was built by a single eruptive center. The filling pattern is controlled by temperature, SiO_2 content,volatile content, magma volume, and the paleolandform. In the short term, the eruptive production of the Changbaishan area is comenditic ash or pumice of a Plinian type eruption. The eruptive volume in future should be smaller than that of the Baguamiao period, and the filling pattern should be PFFC/V,which may cause huge damage to adjacent areas.

Volcanoes and Climate:Sizing up the Impact of the Recent Hunga Tonga-Hunga Ha'apai Volcanic Eruption from a Historical Perspective

An undersea volcano at Hunga Tonga-Hunga Ha'apai(HTHH)near the South Pacific island nation of Tonga,erupted violently on 15 January 2022.Potential climate impact of the HTHH volcanic eruption is of great concern to the public;here,we intend to size up the impact of the HTHH eruption from a historical perspective.The influence of historical volcanic eruptions on the global climate are firstly reviewed,which are thought to have contributed to decreased surface temperature,increased stratospheric temperature,suppressed global water cycle,weakened monsoon circulation and El Niño-like sea surface temperature.Our understanding of the impacts of past volcanic eruptions on global-scale climate provides potential implication to evaluate the impact of the HTHH eruption.Based on historical simulations,we estimate that the current HTHH eruption with an intensity of 0.4 Tg SO_(2)injection will decrease the global mean surface temperature by only 0.004℃in the first year after eruption,which is within the amplitude of internal variability at the interannual time scale and thus not strong enough to have significant impacts on the global climate.

Under the surface:Pressure-induced planetary-scale waves,volcanic lightning,and gaseous clouds caused by the submarine eruption of Hunga Tonga-Hunga Ha'apai volcano

We present a narrative of the eruptive events culminating in the cataclysmic January 15, 2022 eruption of Hunga Tonga-Hunga Ha’apai Volcano by synthesizing diverse preliminary seismic, volcanological, sound wave, and lightning data available within the first few weeks after the eruption occurred. The first hour of eruptive activity produced fast-propagating tsunami waves, long-period seismic waves, loud audible sound waves, infrasonic waves, exceptionally intense volcanic lightning and an unsteady volcanic plume that transiently reached-at 58km-the Earth’s mesosphere. Energetic seismic signals were recorded worldwide and the globally stacked seismogram showed episodic seismic events within the most intense periods of phreatoplinian activity, and they correlated well with the infrasound pressure waveform recorded in Fiji. Gravity wave signals were strong enough to be observed over the entire planet in just the first few hours, with some circling the Earth multiple times subsequently. These large-amplitude, long-wavelength atmospheric disturbances come from the Earth’s atmosphere being forced by the magmatic mixture of tephra, melt and gasses emitted by the unsteady but quasicontinuous eruption from 0402±1–1800 UTC on January 15, 2022. Atmospheric forcing lasted much longer than rupturing from large earthquakes recorded on modern instruments, producing a type of shock wave that originated from the interaction between compressed air and ambient(wavy) sea surface. This scenario differs from conventional ideas of earthquake slip, landslides, or caldera collapse-generated tsunami waves because of the enormous(~1000x) volumetric change due to the supercritical nature of volatiles associated with the hot,volatile-rich phreatoplinian plume. The time series of plume altitude can be translated to volumetric discharge and mass flow rate. For an eruption duration of ~12 h, the eruptive volume and mass are estimated at 1.9 km^(3) and~2 900 Tg, respectively, corresponding to a VEI of 5–6 for this event. The high frequency and intensity of lightning was enhanced by the production of fine ash due to magma-seawater interaction with concomitant high charge per unit mass and the high pre-eruptive concentration of dissolved volatiles. Analysis of lightning flash frequencies provides a rapid metric for plume activity and eruption magnitude. Many aspects of this eruption await further investigation by multidisciplinary teams. It represents a unique opportunity for fundamental research regarding the complex, non-linear behavior of high energetic volcanic eruptions and attendant phenomena, with critical implications for hazard mitigation, volcano forecasting, and first-response efforts in future disasters.

Relationship between earthquake and volcanic eruption inferred from historical records

A large number of seismic records are discovered for the first time in the historical materials about Wudalianchi volcanic group eruption in 1720~1721, which provides us with abundant volcanic earthquake information. Based on the written records, the relationship between earthquake and volcanic eruption is discussed in the paper. Fur-thermore it is pointed that earthquake swarm is an important indication of volcanic eruption. Therefore, monitoring volcanic earthquakes is of great significance for forecasting volcanic eruption.

New Theory of Effusive and Explosive Volcanic Eruptions

In this study, we presented new theory of effusive and explosive of volcanic eruptions. New explanation of eruption mechanisms was done by using the Elemental Buoyancy Theory and new K-Th-U structure of Earth, developed early by author. During investigation of effusive eruptions, it was given clear answer on the question why the light chemical elements, mainly silicon and sulfur compound, currently dominate in the volcanic ashes, gases, and in the magma lavas. At investigation of explosive mechanism, we analyzed 38 strong eruptions with Volcanic Explosivity Index (VEI) more than 4+. It was shown that there is a link between the planet configurations and volcanic eruptions. It can be found that volcano eruptions occurred at the different types of planet alignments. The phenomenon does depend neither on planet mass nor on the relative positions of planets. Also the phenomenon does not depend on the distance between planets, but often eruptions were observed when the distances between planets are multiple units. Also in work, it was demonstrated that the planet alignment affects not only natural processes on the Earth, but also impact the Sun activity. Based on the comparison phenomenon on the Earth and Sun, we get new mechanism to rapidly rising up pressure under the lithospheric planes by gravity vortexes. This gravity vortex was called as terrestrial magmatic protuberances.

Study on relationship between historical volcanic eruptions and historical strong earthquakes in China and its adjacent regions

This thesis lists and describes 6 pairs of tectonic events, i.e ., historical volcanic eruptions associated with historical strong earthquakes, based on the analysis for the records of historical volcanic eruptions and historical strong earthquakes in China and its adjacent region since the first record. And discusses the relationship between historical eruptions and strong earthquakes by means of analyzing the characteristics of tectonic events themselves, plate movement, regional seismicity, and regional stress environment in China and its adjacent region.

THE RELATIONSHIP OF LARGE VOLCANIC ERUPTION IN THE WORLD AND THE SUMMER DROUGHT/FLOOD IN CHINA

Based on data in the last 500 years for strong volwtc aedvity and the sununer drought/flood types available in China, the statistical relatons 0f the volcanic eruptions in seasons and several ropons and the drowtood types and grade index of main wions in China have ban inveStigned. The possible teleconnection bforan flood in the Yangtze hiver and the Huaihe foveL Valleys in 1991 and the volcanic eruption of Mt. Pinatubo in June of 1991 has bam also exathened. It is found that ehas of volcanic eruption in differen ropons in the worid vary on droguood in diffend edons of China, but in some cases the the is absolutely opposite in respect of the summer drowood. Statshcal test shows that in terms of stud confidence levels of the reation for dividing the volcanic eruptions as several ropons are higher than that for volcanic eruPhon in the worid as Whole.

Influence of volatile degassing on initial flow structure and entrainment during undersea volcanic fire fountaining eruptions

Release of dissolved volatiles during submarine fire fountaining eruptions can profoundly influence the buoyancy flux at the vent. Theoretical considerations indicate that in some cases buoyant magma can be erupted prior to fragmentation (~75% vesicle volume threshold). Laboratory simulations using immiscible fluids of contrasting density indicate that the structure of the source flow at the vent depends critically on the relative magnitudes of buoyancy and momentum fluxes as reflected in the Richardson number (Ri). Analogue laboratory experiments of buoyant discharges demonstrate a variety of complex flow structures with the potential for greatly enhanced entrainment of surrounding seawater. Such conditions are likely to favor a positive feedback between phreatomagmatic explosions and volatile degassing that will contribute to explosive volcanism. The value of the Richardson number for any set of eruption parameters (magma discharge rate and volatile content) will depend on water depth as a result of the extent to which the exsolved volatile components can expand.

Predictions of Galapagos Volcanic Eruption, El Niño, Ecuadorian Earthquake, Global Volcanic Eruption and Forest Fire by Sunspot Number

The earthquake number was correlated (R2 = 0.8781) with the volcano number in the East Pacific and Central American countries. The year of volcanic eruptions in the Galapagos Hot Spot (GHS) was proportional to the year of El Ni&#241o events (R2 = 0.9939) as well as to the year of earthquake events (R2 = 0.9943) in Ecuador, Colombia, and Peru from 1977 to 2016. Therefore, there can be El Ni&#241o and earthquake events in Ecuador, Colombia and Peru if there are strong volcanic eruptions either from aboveground volcanoes or undersea seamounts in the GHS during the maximal sunspot number’s period. Global volcanic eruptions were occurred during the maximal temperature departure, the latter being reversely proportional (R2 = 0.4512) to the sunspot number from 1980 to 2019. Forest fires occurred in middle latitude countries (South Korea, California, western Russia, Australia) around 35 degree from Pacific Equator during La Ni&#241a events at the time of the minimal sunspot number. Since there were intense forest fires in South Korea, Australia and California in 2019, more are expected in 2030 due to the 11 year cyclical variation in the sunspot number. The sequence of forest fires can be schematically summarized as below. 1) La Ni&#241a event in Equator causes the low vapor pressure of water due to the low sea surface temperature (SST);2) There is the pumping of freshwater from the warm Pacific Ocean to cold Equator with simultaneous transfer of heat (warm Pacific Ocean to cold Equator) and mass (water enriched Pacific Ocean to water lean Equator);3) Strong winds from dry zone pass Mountains to cause the forest fires in the residential land with bushes and trees. 4) According to the Bernoulli’s principle, the pressure gradient between the high Mountains and the low Ocean, induces the decrease of static velocity gradient for vigorously upwards flares in the Mountains and the residential land during the forest fires, which may be why it is difficult to extinguish the forest fires until burnt up bushes and trees in the Mountains and residential land with serious damages. Most effective solution to forest fires is to change the events from La Ni&#241a to El Ni&#241o for reductions of temperature and pressure gradients by Gay-Lussac’s law. Such a transition may be induced by artificial submarine volcanic eruptions among volcanoes of Fernandina, Sierra Negra and Wolf in the GHS for Korea and California. As for Australia, artificial volcanic eruptions can be caused in huge underwater volcano chain in Tasmania. The strong damages of forest fires in South Korea, Australia and California were observed in the period of the minimal sunspot number, as were in October of 2019 to February of 2020. Simultaneous transfers of momentum (velocity), heat (temperature) and mass (freshwater) were occurred from the dry zone or the hot Deserts via the Mountains and the residential land with bushes and trees to the cold Sea or Ocean. It is expected the lowest SST during the year of the minimal sunspot number to induce the strong damages of forest fires, as was in South Korea, Australia and California during the years from 2019 to 2020. CO2 emissions in Australia showed 34.5% increase, 70% coal power and no nuclear power to induce bushfires because of increases of ozone hole area and UV radiation for the hot land in the period of La Ni&#241a. Fossil fuel operation should be cut down to decrease the ozone hole area and UV radiation for weak bushfires in Australia. A few coming years may still have bushfires in Australia although their damages may not be as terrible as was in 2020. A simple remedy can be the reduction of CO2 emissions as low as possible. It was proposed that the maximal sunspot number induced El Ni&#241o event, GHS volcanic eruption and Ecuadorian earthquakes, while the minimal sunspot number induced La Ni&#241a events in Ecuador, Colombia, Peru and intense forest fires in middle latitude countries of South Korea (forest fires), Australia (bushfires) and California (wildfires).

Hypothetical Physics and Chemistry of Volcanic Eruptions: The Doorway to Their Prediction

This article presents a further development of the hypotheses concerning the possibility of predicting (“tectonic”) earthquakes [1]. Those hypotheses are based on the conversion of all types of released energy into heat and active chemical substances. One of the important sources of this phenomenon is the release of the latent energy trapped and stored during the Earth’s accretion. The latent energy of primordial hydrogen and helium escaping from the Earth’s core and lower mantle causes degassing processes [2] [3]. This latent energy converts into totally different types of chemical, electromagnetic and thermal energies of active compounds that are responsible for the major endogenic terrestrial processes. The dominating theories in seismology and volcanology are that an earthquake results from a sudden slip of a tectonic fault and that only magma and the gases contained in magma supply the volcanic energy resulting in the conclusions that earthquakes and eruptions are unpredictable. Volcanic eruption is considered herein to be a special case of the earthquake-process in which earthquake hypocenters rise to the Earth’s surface. A possible solution is proposed ([1] and herein) based on the analyses of the physicochemical processes as participants in earthquake and eruption preparations (foreshocks - major shock - aftershocks - volcanic eruptions) and on the characteristic rates of reflection of these processes on the Earth’s surface. Influences of Sun-Moon-tides and volcanic (“harmonic”) tremors are analyzed from physical-chemical point of view. The case of the 1980 eruption of Mount St. Helens and the proposed monitoring of the recommended additional data provides a way of selecting a complex of reliable earthquake and volcanic eruption precursors.

Harmful Algal Blooms Associated with Volcanic Eruptions in Indonesia and Philippines for Korean Fishery Damage

Harmful Algal Blooms (HAB) were analyzed to trace the outbreak of dinoflagellate Cochlonidium polykrikoides on the Korean coast from 1993 to 2019 along with relationship to volcanic eruptions. Parameters associated with blooms and fishery damage were sunspot number, El Ni?o/La Ni?a events, Kuroshio Current, and volcanic eruptions in the South China Sea including Indonesia and the Philippines. HAB development was halted in seawater due to the sulfur compounds (H2S, SO2, sulfates) from volcanic eruptions inducing the deficiency of the dissolved iron (Fe) in the seawater. Cochlonidium polykrikoides blooms could be predicted by the minimal sunspot number during La Ni?a event or weak volcanic eruptions in Indonesia and the Philippines. On line monitoring of HAB was suggested using a prototype detector of Cochlonidium polykrikoides at wavelength of 300 nm with the concentration linearity (R2 = 0.9972) between 1000 and 6000 cells/ml. HABs on the Korean coast were negligible when there were volcanic eruptions in either Indonesia or Philippines from May to August. Fishery damage was linearly proportional (R2 = 0.2986) to the maximal concentration of HAB while 5000 cells/ml was the minimal concentration of HAB with high linearity (R2 = 0.7629), caused by old cysts of Cochlonidium polykrikoides on the Korean coast rather than the fresh ones carried by the Kuroshio Current from the Philippines. Fishery damage was reversely proportional to the number of sunspots;the maximal number of sunspots induced frequent volcanic eruption in Indonesia and the Philippines for retardation of HAB with less fishery damage in Korea while the minimal number of sunspots caused less volcanic eruptions for thereby enhancing HAB resulting in more fishery damage. It was proposed that a yellow LED be used at 590 nm as a photochemical expellent as well as H2S gas bubbling at a 0.5 meter depth on the surface of the fish cage to inactivate chemically Cochlonidium polykrikoides due to the deficiency of essential iron in the seawater. In addition, the physical method of blanketing the cage cloth with smaller pore diameter than that of HAB was used for prevention of Cochlonidium polykrikoides penetrating into the fish cage.

Impacts of major volcanic eruptions over the past two millennia on both global and Chinese climates:A review

Major volcanic eruptions(MVEs)have attracted increasing attention from the scientific community.Previous studies have explored the climatic impact of MVEs over the past two millennia.However,proxy-based reconstructions and climate model simulations indicate divergent responses of global and China’s regional climates to MVEs.Here,we used multiple data from observations,reconstructions,simulations,and assimilations to summarize the historical facts of MVEs,the characteristics and mechanisms of their climatic impact,and directions for future research.We reviewed volcanic datasets and determined intensive MVE periods;these periods corresponded to the years 530–700,1200‒1460,and 1600‒1840 CE.After tropical MVEs,a substantial cooling effect is observed throughout the globe and China on the interannual-interdecadal time scales but an inconsistent cooling magnitude is detected between reconstructions and simulations.In the first summer after tropical MVEs,a decrease in global and monsoonal precipitation is observed.In reconstructions and simulations,an increased precipitation is seen for the Yangtze River Basin,while large uncertainties in precipitation changes are present for other regions of China.Decadal drought can be induced by frequent eruptions and volcanism superimposed on low solar irradiation and internal variability.MVEs affect climate directly through the radiative effect and indirectly by modulating internal variability,such as the El Niño‒Southern Oscillation(ENSO)and Atlantic Multidecadal Oscillation(AMO).However,changes in the phase,amplitude,and periodicity of ENSO and AMO after MVEs and the associated mechanisms remain controversial,which could account for model-reconstruction disagreements.Moreover,other internal variability,uncertainties in reconstruction methods and aerosol‒climate models,and climate background may also induce model-reconstruction disagreements.Knowledge gaps and directions for future research are also discussed.

Southern Hemisphere Volcanism Triggered Multi-year La Niñas during the Last Millennium

To explain the recent three-year La Niña event from 2020 to 2022,which has caused catastrophic weather events worldwide,Fasullo et al.(2023)demonstrated that the increase in biomass aerosol resulting from the 2019-20 Australian wildfire season could have triggered this multi-year La Niña.Here,we present compelling evidence from paleo-proxies,utilizing a substantial sample size of 26 volcanic eruptions in the Southern Hemisphere(SH),to support the hypothesis that ocean cooling in the SH can lead to a multi-year La Niña event.This research highlights the importance of focusing on the Southern Ocean,as current climate models struggle to accurately simulate the Pacific response driven by the Southern Ocean.

Influence of volcanic activity on vegetation succession and growth environment on the hillslope of Sakurajima Volcano in southern Kyushu,Japan

This study was conducted in order to examine the influence of long-term volcanic activity on vegetative succession and growth on the slope of Sakurajima in southern Kyushu, Japan. We investigated the vegetation,depth of the volcanic ash layer, and dry density and p H of the surface soil at six places on the north-northwestern slope, 2.3–3.4 km from the Minami-dake crater, where a layer of pumice stone was deposited by the Taisho eruption in 1914. The height and diameter at breast height（DBH） of the trees increased with increasing distance from the Minami-dake crater, as did the number of individuals and species, and basal area. The Shannon–Wiener diversity index（H＇） demonstrates that vegetative succession is significantly affected by distance from the Minami-dake crater, as areas farther from the crater exhibited later seral stages. Comparison of the diversity index and species number of the crater region with that of the climax forest in Kagoshima indicates that vegetative growth alone cannot advance succession in the study area, as the local vegetative community is heavily influenced by the harsh environmental conditions associated with continual exposure to long-term volcanic activity. Seral stage, ash layer depth,dry density, and p H of the soil surface layer are governed by distance from the Minami-dake crater. The results of this study indicate that conditions for vegetative growth and succession improve with increasing distance from the source of constant volcanic activity. Thus, soil development is promoted by the acidification of the soil, which decreases the dry density and p H of the soil surface layer.The introduction of plant species resistant to volcanic ash and gas is recommended to promote soil development and improve the infiltration capacity of the soil.

Geological Controls on Seismic indicators of Volcanic Gas Reservoirs:A Case Study from the Changling Fault Depression of Songliao Basin,China

The Songliao basin in northeast China is a Mesozoic rift basin characterized by Mesozoic and Cenozoic hydrocarbon systems.The Changling fault depression located in the south of the Songliao Basin,