A Potential Flood Hazard Caused by Tianchi Volcano Eruption in Changbai Mountain, Northeast China

Geohazards appear to be increasing in frequency globally. It is of necessity to actively manage these natural hazards to minimize loss of life and property. From an early warning perspective, this paper stresses the potential fatal flood hazard represented by the huge volume of water in Tianchi Lake, the unique geography of Changbai Mountain, and the limited flood control ability in the upstream of the Songhua River. Northeast Asian countries should keep a watchful eye on the Changbai volcano cooperatively, and Chinese government especially needs to prepare plans for fighting a flood in advance.

Potential Impact of Tonga Volcano Eruption on Global Mean Surface Air Temperature

The undersea volcano,located in the South Pacific island nation of Tonga,violently erupted from 14 to 15 January 2022.The Tonga volcano eruption has aroused extensive discussion in the climate change field.Some climatologists believe that this event will cause little effect on global climate change while others insist that it will trigger“the year without a summer”as the Tambora eruption did in 1815.How will the Tonga volcano eruption affect global climate change?Based on the indices of past volcanic eruptions and the eruption data of El Chichón volcano in 1982,we use a simplified radiation equilibrium model to quantify the stratospheric aerosol radiative forcing and the change in global mean surface air temperature(Ts)caused by the Tonga volcano eruption.The results show that the global average Ts will decrease by about 0.0315-0.1118℃in the next 1-2 years.The Tonga eruption will slightly slow down the global warming in a short period of time,but it will not change the global warming trend in the long term.In addition,we propose a generalized approach for estimating the impact of future volcanic eruption on global mean T_(s).

Activity of Changbaishan Tianchi Volcano Since Late Pleistocene——The Constrain From Geochronology of High Precision U-Series Tims Method

samples of lava and pumice from the cone of Changbaishan Tianchi Volcano, Jiling, China, were dated by using high precision U-series TIMS method. We conclude that the bottom of the cone formed before 350 ka, the middle part in 70～80 ka, the upper during 20～1ka, and the top less than 1ka, and the age based periods of the volcano eruption since Late Pleistocene is given as follows: >350ka,70ka,18～25ka,10ka, 4C5ka, 1～0.75ka, which may offer the basis for the study of volcanic disaster in future. In addition, the principle of dating young volcanic rocks by using U-series TIMS method is introduced briefly. Differentiation characteristics of U and Th in different minerals of the volcanic rocks are discussed, and the ability producing isochrons, based on U and Th differentiation, are discussed. In the last part of the paper, the closure of samples to the elements U and Th, which is important for age results, is discussed by using ( 234 U/ 238 U) radioactivity ratio which can be used to monitor if the samples have been weathered or eroded or leached since the time they formed. In this study, all samples have ( 234 U/ 238 U) activity ratios within 1% of secular equilibrium (( 234 U/ 238 U) radioactivity ratios are unity), indicating no disturbance of the 234 U～ 238 U system. All of these discussions show that the TIMS method is good to date Tianchi volcanics and the results are reliable.

Coupling between the Cenozoic west Pacific subduction initiation and decreases of atmospheric carbon dioxides

At the beginning of the Cenozoic,the atmospheric CO_(2)concentration increased rapidly from~2000 ppmv at 60 Ma to~4600 ppmv at 51 Ma,which is 5–10 times higher than the present value,and then continuous declined from~51 to 34 Ma.The cause of this phenomenon is still not well understood.In this study,we demonstrate that the initiation of Cenozoic west Pacific plate subduction,triggered by the hard collision in the Tibetan Plateau,occurred at approximately 51 Ma,coinciding with the tipping point.The water depths of the Pacific subduction zones are mostly below the carbonate compensation depths,while those of the Neo-Tethys were much shallower before the collision and caused far more carbonate subducting.Additionally,more volcanic ashes erupted from the west Pacific subduction zones,which consume CO_(2).The average annual west Pacific volvano eruption is 1.11 km~3,which is higher than previous estimations.The amount of annual CO_(2)absorbed by chemical weathering of additional west Pacific volcanic ashes could be comparable to the silicate weathering by the global river.We propose that the initiation of the western Pacific subduction controlled the long-term reduction of atmospheric CO_(2)concentration.

全球海啸相关研究进展综述

With the advancement of the global economy,the coastal region has become heavily developed and densely populated and suffers significant damage potential considering various natural disasters,including tsunamis,as indicated by several catastrophic tsunami disasters in the 21st century.This study reviews the up-to-date tsunami research from two different viewpoints:tsunamis caused by different generation mechanisms and tsunami research applying different research approaches.For the first issue,earthquake-induced,landslide-induced,volcano eruption-induced,and meteorological tsunamis are individually reviewed,and the characteristics of each tsunami research are specified.Regarding the second issue,tsunami research using post-tsunami field surveys,numerical simulations,and laboratory experiments are discussed individually.Research outcomes from each approach are then summarized.With the extending and deepening of the understanding of tsunamis and their inherent physical insights,highly effective and precise tsunami early warning systems and countermeasures are expected for the relevant disaster protection and mitigation efforts in the coastal region.

Tephra Discovered in High Resolution Peat Sediment and Its Indication to Climatic Event

Floating tephra was deposited together with ice core, snow layer, abyssal sediment, lake sediments, and other geological records. It is of great significance to interpret the impact on the climate change of volcanic eruptions from these geological records. It is the first time that volcanic glass was discovered from the peat of Jinchuan （金川） Maar, Jilin （吉林） Province, China. And it is in situ sediments from a near-source explosive eruption according to particle size analysis and identification results. The tephra were neither from Tianchi （天池） volcano eruptions, Changbai （长白） Mountain, nor from Jinlongdingzi （金龙顶子） volcano about 1 600 aBP eruption, but maybe from an unknown eruption of Longgang （龙岗） volcano group according to their geochemistry and distribution. Geochemical characters of the tephra are similar to those of Jinglongdingzi, which are poor in silica, deficient in alkali, Na2O content is more than K2O content, and are similar to distribution patterns of REE and incompatible elements, which helps to speculate that they originated from the same mantle magma with rare condemnation, and from basaltic explosive eruption of Longgang volcano group. The tephra, from peat with age proved that the eruption possibly happened in 15 BC-26 AD, is one of Longgang volcano group eruption that was not recorded and is earlier than that of Jinglongdingzi about 1 600 aBP eruption. And the sedimentary time of tephra is during the period of low temperature alteration, which may be the influence of eruption toward the local climate according to the correlativity of eruption to local temperature curve of peat cellulose oxygen isotope.

Clinopyroxene and Fe-Ti oxides for correlating the ash from Changbaishan Millennium eruption

Volcanic glass compositions and tephra layer age are critical for anchoring their sources and correlating among different sites; however, such work may be imprecise when the tephra has varied compositions. The ash from Changbaishan Millennium eruption(940s AD), a widely distributed tephra layer, has been detected in the far-east areas of Russia, the Korean Peninsula, Japan, and in Greenland ice cores. There are some debates on the presence of this tephra from sedimentary archives to the west of Changbaishan volcano, such as lake and peat sediments in the Longgang volcanic field. In this paper, major element compositions for clinopyroxene and Fe-Ti oxides were performed on proximal tephra from Changbaishan and the Millennium eruption ash record in Lake Sihailongwan. Clinopyroxene and Fe-Ti oxides microlites from Sihailongwan show augite-ferroaugite and titanmagnetite compositions, similar to those from dark pumice in Changbaishan proximal tephra, but different from the light grey pumice, which has ferrohedenbergite and ilmenite microlite compositions. This result implies that the tephra recorded in Sihailongwan was mainly from the trachytic eruptive phase of the Millennium eruption, and the rhyolitic eruptive phase made a relatively small contribution to this area. Analyzing clinopyroxene and Fe-Ti oxides microlites is a new method for correlating tephra layers from Changbaishan Millennium eruption.

A Set of Three Technologies Will Save Mankind from Climate Change in the Most Inexpensive Way Possible

This paper formulates a set of three technologies that should deal with the greatest threat to mankind—climate change at the lowest cost.The main technology will be“Sunny Rain”.It considers technology to prevent eruptions of submarine volcanoes at shallow depths and technologies that provide scalable and impactful solutions to reduce carbon emissions across diverse industries as complementary technologies used to reduce cost.A list of submarine volcanoes at shallow depths that are likely to spew waterborne dust into the atmosphere has begun to be created.If the governments of Japan,Italy,and Greece,which have submarine volcanoes at shallow depths(Kiki,Marsili,Columbo),prevent eruptions of these volcanoes,it will provide electricity to these countries,save many of their citizens from death,and save humanity from the greatest threat—climate change—in the most inexpensive way possible!