Northern Korean Peninsula Research Articles

Initiation of the Unazuki Belt, Southwest Japan, during the Carboniferous as an island arc system along the North China Craton

The Unazuki Belt, Southwest Japan, is a part of the Hida Belt, which is characterized as a plutono-metamorphic complex with a continental affinity formed between the late Paleozoic and early Mesozoic. The Unazuki Belt is known to be an important tectonic unit for the tectonic correlation between the proto-Japan and East Asian continents as it records Permo–Triassic tectono-thermal events, however, comprehensive chronology of the Unazuki Belt including the timing of the initiation of this Belt is yet unclear. The present study reveals certain Carboniferous magmatic and sedimentation events from the Unazuki Belt and their tectonic implications for the first time as follows. Zircon U–Pb age dating results and whole-rock geochemical compositions show that the protoliths of metagranite and metatrachyandesite in the Unazuki Belt formed at 328.2 ± 4.4 Ma and 332.8 ± 2.2 Ma, respectively, in an arc tectonic setting. Most metasedimentary rocks of the Unazuki Belt have the youngest detrital zircon grains of ~ 300 Ma with the Carboniferous single cluster at ~ 340–300 Ma without any Pre-360 Ma detrital zircon grains. However, one metasedimentary rock with Precambrian detrital zircons (~ 20%) has the youngest detrital zircon age of ~ 252 Ma, and ~ 66% of detrital zircons show a Permian age. Most of the εHf(t) values of zircon grains from all the studied Unazuki Belt samples, including the metasedimentary and metaigneous rocks with Carboniferous ages (~ 360–300 Ma) are positive (+ 6– + 18), whereas those of the zircon grains with Permian ages (~ 280–260 Ma) show wide variations between + 16 and -23. The whole-rock geochemical compositions of the ~ 300 Ma metasedimentary rocks of the Unazuki Belt show an island arc tectonic setting, whereas those of ~ 252 Ma metasedimentary rock have a continental arc affinity. These new data suggest that (1) igneous and sedimentary rocks in the Unazuki Belt formed in the island arc tectonic setting separated from the margin of continental crust during the Carboniferous but shifted to the continental arc tectonic setting during the latest Permian, (2) the collision between the island arc and continental arc may have caused the intermediate-P/T metamorphism during the Permian in the Unazuki Belt. The Carboniferous island arc tectonic setting in the Unazuki Belt indicates that the Hida Belt, including the Unazuki Belt, formed not at the margin of the South China Craton where Carboniferous subduction is absent but on the continuous subduction zone located along the eastern margin of the North China Craton, including the eastern margin of the northern Korean Peninsula where Carboniferous subduction occurred.Graphical

조선시대 한반도 북부 지역의 越境地 분포와 그 역사적 성격

조선시대 한반도 북부 지역의 越境地 분포와 그 역사적 성격

The Neoproterozoic continental extension tectonic event in the Chuncheon area of the northern Gyeonggi massif in the Korean Peninsula and its implication for the tectonic correlation between the Korean Peninsula and China

The Meso-Neoproterozoic Gubongsan group in the Chuncheon area of the northern Gyeonggi massif in the southern Korean Peninsula was studied to check its correlation with the Meso-Neoproterozoic rocks of the Sangwon system in the northern Korean Peninsula and those of the Qingbaikou system in the southeastern margin of the North China craton. The Gubongsan group consists of the Pyeongchonri, Siniri, and Gamjeongri formations and the upper limit of sedimentation ages of each formation are 1058 Ma, 978 Ma, and 845 Ma, respectively. The detrital zircons in the Pyeongchonri and Siniri formations have two age peaks of ∼1.6–1.5 Ga and 1.2–1.1 Ga. The detrital zircons in the Gamjeongri formation has an age peak of 0.9 Ga. The Gubongsan group was intruded by metabasite and meta-intermediate rock ca. 888–795 Ma. To the south of the Gubongsan group, metabasite intruded ca. 910 Ma. These igneous rocks are plotted in the within-plate basalt field and have enriched LREE without negative Nb, Ta, and Ti anomalies. They show εHf(t) values from −1.72 to 14.10 and are plotted between E-MORB and OIB within the MORB array, representing that they formed from the juvenile mantle. This study represents that the sedimentation in the Gubongsan group occurred during Neoproterozoic in the extensional rifting environment with igneous activities in the later stage of extension. The metabasite in the Gubongsan group shows similar Neoproterozoic emplacement age and extension-related geochemical characteristics to the Sariwon sill in the Sangwon system located in the southern Nangnim massif, and the Dalian and Chulan sills in the Qingbaikou system of the southeastern margin of the North China craton. Not only the correlation of metabasite but also the youngest age of the detrital zircons and age provenance in the sedimentary rocks of the Gubongsan group are similar to those of the Sangwon system and the Qingbaikou system. This study represents that the Meso-Neoproterozoic rocks in the Gubongsan group can be correlated with those in the Sangwon system and the Qingbaikou system. These correlations indicate that the northern Gyeonggi massif can be correlated with the southern Nangnim massif and the southeastern margin of the North China craton.

CORDEX-EA Phase 2 다중 지역기후모델 앙상블을 이용한 전지구 온난화 제한 목표(1.5, 2.0℃)하에서의 한반도 미래 기온 전망

This study presents a future projection of temperature over the Korean Peninsula (KP) under the global warming targets of 1.5℃ and 2.0℃ set in the 2015 Paris Agreement. For projection, simulation data from the multi-Regional Climate Model (RCM) ensemble in Coordinated Regional Climate Downscaling Experiment (CORDEX)-East Asia (EA) Phase 2 are used. Under the 2.0℃ (1.5℃) global warming condition, mean temperature over KP would increase 2.13℃ (1.51℃) compared to the present period (1985 ~ 2005 years). Extreme minimum and maximum temperature intensity indices (TNn and TXx) would also increase 2.61℃ (1.91℃) and 2.38℃ (1.58℃). In addition, changes in probabilities of extreme temperature events that occurs once in 20 years during the present period are investigated. Extreme cold events would occur once in 28.9 years (22.6 years) and warm events once in 5.9 years (7.2 years). Meanwhile, there are several noteworthy points about the future projection. The temperature over KP would increase more over the northern KP than the southern KP and this feature is more distinct in TNn. The uncertainties of the projection are higher for the 1.5℃ warming condition than the 2.0℃ warming condition and for extreme temperature versus mean temperature. The spatial pattern of change in extreme temperature frequency is different from that of intensity. In other words, a smaller increase in the frequency of extreme cold events is expected over the inland KP.

RE-MAKING ANIMAL BODIES IN THE ARTS OF EARLY CHINA AND NORTH ASIA: PERSPECTIVES FROM THE STEPPE

AbstractThe Iron-Age Eurasian nomads created and circulated elaborate metalworks embellished with images of entwined, abbreviated, or contorted zoomorphic anatomies. This approach to zoomorphism has entered scholarly discourse under the blanket name “animal style,” a term often used to describe a vast corpus of zoomorphic images associated with the arts of steppe pastoralists. Numerous Warring States burials across the Ordos Loop indicate the transmission and adaptation of steppe-inspired zoomorphism into the funerary cultures of China's northern zone (beifang diqu 北方地區) and the Eastern Steppe more broadly. In the Han dynasty, animal-style images seem to have been transmitted even more widely, reaching China's southern periphery at the Kingdom of Nanyue 南越 and Lelang 樂浪 in the northern Korean peninsula. The Xianbei hegemony in the post-Han period marked a new trajectory for these designs, which reached Kofun Japan in the fifth century. Thus, the original trans-steppe visual formula underwent significant regional and local translations on a material and conceptual level to fit already established Chinese design strategies, techniques, and conceptions of animality. In this essay, I explore the regional alterations applied to the “supra” animal-style visuality in the Chinese northern periphery and other regions of Chinese political influence in North and Central Asia. In so doing, I seek to understand the swift entry of nomadic visual tropes, namely a specific “pars-pro-toto” device, into the visual vocabulary of early Chinese craftsmen from the Eastern Zhou to the Northern dynasties.

Decreasing or increasing trends? Evidence of long-term change in river discharge over the northern Korean Peninsula, 1951–2010

Decreasing or increasing trends? Evidence of long-term change in river discharge over the northern Korean Peninsula, 1951–2010

Influence of seawater intrusion on the hot springs in a coastal area: The case of the Anak-Sinchon Uplift, Korean Peninsula

Temperatures and chemical compositions of hot springs are decisive of their roles in heating, power-generation, therapeutic applications and recreational activities. However, the influence of seawater intrusion on hot springs are still not fully understood. Typical ten hot springs in and around the Anak-Sinchon Uplift in a coastal area of the northern Korean Peninsula were investigated. All the hot springs were near-neutral to weakly alkaline. High TDS value of 25300 mg/L was found at the hot spring closest to the coastline. TDS values, and concentrations of Na+, K+, Ca2+, Cl− and SO42− in the hot spring waters near the coast showed decreasing trends with the distance from the coastline. According to the calculation of seawater fraction, three hot springs near the coast were contaminated by seawater. Temperatures of the geothermal reservoir were estimated to range from 103 to 170 °C, which were interpolated by thin plate spline to predict the local trend of the reservoir temperature distribution. Mg2+ concentration was used to determine the time order between the heating process and seawater intrusion. Among the three seawater-contaminated hot springs, very low Mg2+ concentrations in two hot spring waters probably indicate that they were mixed with seawater before being heated in the geothermal reservoir and not affected by seawater intrusion again afterwards; relatively high Mg2+ concentration in the hot spring water closest to the coastline likely indicates that it was mixed with seawater again during the ascent from the geothermal reservoir. The geochemical modeling performed with PHREEQC indicates that dolomitization of calcite and precipitation of anhydrite were the dominant water-rock interactions for the seawater-contaminated hot spring waters.

A brief review of the Precambrian geology of the northern Korean Peninsula

북중국판의 일부인 한반도 북부의 선캠브리아기 지질에 대한 이해는 북중국판의 이해와 한반도 남부와 일본이 북동아시아 선캠브리아기 암석들과 어떠한 연관성을 갖는지를 밝히는데 중요하다. 한반도 북부의 주 구성원은 낭림육괴와 관모육괴이다. 두 육괴에서는 시생대 TTG와 화강암질 편마암이 발견되었고 이들은 여러 번에 걸쳐 변성작용을 받았다. 특히 고원생대 변성작용은 한반도 북부의 모든 선캠브리아기 암석에 영향을 주었다. 한반도 북부에는 변성퇴적암으로 구성된 고원생대 마천령층군과 증산충군이 분포한다. 이들 암석은 1950-1785 Ma 시기에 변성작용과 그에 수반된 용융을 경험하였다. 증산층군내 고변성암은 북중국판 동부와 마찬가지로 시계 방향의 압력-온도 진화를 경험하였다. 그리고 한반도 북부에서는 고원생대 화성작용이 광범위하게 일어났으며 그 중 1950-1800 Ma 화강암들이 가장 많이 나타나며 I-type, S-type, 그리고 섬장암류로 분류된다. I-type과 섬장암류 화성암들은 고원생대 조산운동이 끝나는 시기에 형성되었으며 S-type 화강암은 고변성작용 시기에 일어난 부분 용융에 의해 형성되었다. 북중국판내 나타나는 창천층군과 지시안 층군을 제외한 모든 중원생대-신원생대 층군에 대비되는 퇴적암들이 한반도 북부에서 나타난다. 한반도 북부의 중원생대 황해층군은 옹진 화강암과 시기적 지리적으로 관련성이 있으며 이들은 황해 열곡작용 시기에 의해 형성되었다. 신원생대 사리원 암상은 북중국판의 남쪽과 동쪽 경계를 따라 발달되어있던 Xu-Huai-Lv-Da-평남 열곡 시스템내에서 일어난 지질작용에 의해 형성되었다. 한반도 북부 고원생대 지구조운동은 콜롬비아 초대륙의 형성과 관련이 있으며 중원생대와 신원생대 지질작용은 아직 확실치는 않지만 로디니아 초대륙의 분열과정과 관련이 있다고 알려져있다.

Provenance and distribution networks of the earliest bronze in the Maritime Territory (Primorye), Russian Far East

Metal artifacts from the Paleometal Epoch (ca. 1100 BC–400 AD) of the Primorye (Russian Far East) have shed new light on the introduction of the earliest bronzes into the Pacific coastal areas of prehistoric Eurasia. However, little is known about raw material circulation and the role of metal in the context of inter-regional exchange. This paper investigates 12 copper artifacts from major Paleometal settlements using alloy composition, trace elements, and lead isotopes to explore the metal sources and distribution networks. The results suggest that most objects are made of a copper-tin alloy, but some have arsenic as a significant minor element . Geologically, copper is unlikely to have come from local ore sources, but rather from the Liaoxi corridor and Liaodong Peninsula in Northeast China. This may indicate an inland route of metal trade across Northeast China or alternately, a coastal route via the northern Korean Peninsula. Archaeologically, the combined study of artifact typology and chemistry indicates two possible origins for the metal: the Upper Xiajiadian culture in Northeast China and Slab Grave culture in Mongolia/Transbaikal. Remarkably, the connection with Upper Xiajiadian communities parallels the transport route along which millet agriculture spread from Northeast China to the Primorye during the Neolithic.

In situ zircon U[sbnd]Pb dating of Jurassic granitoids in North Korea and its tectonic implications

Jurassic granitoids formed during the Daebo period of magmatism are common throughout the northern Korean Peninsula, but precise geochronological and geochemical data for these granitoids are lacking. In this study, 16 granitic rocks from 10 Jurassic plutons in the Rangrim Massif and Imjingang Belt, including diorite, biotite granite, two-mica granite, granodiorite, porphyry granite, and leucogranite, were subjected to in situ zircon UPb dating. The ages range from 197 ± 3 to 164 ± 4 Ma. Combined with previously published age data for the Jurassic granites, it is apparent that the Daebo period magmatism occurred mainly in the Early and Middle Jurassic (199–163 Ma). Early Jurassic granites are mostly exposed in the northern and southern Korean Peninsula (i.e., the Tumangang Belt and Kwanmo sub-massif in the north and Yeongnam Massif in the south). Middle Jurassic granites are mainly distributed in the central Korean Peninsula. These granites are peraluminous, high-K calc-alkaline or shoshonitic, and I- and highly fractionated I-type granites. The similar timing of magmatism and large-scale strike-slip shear structure demonstrates that the Daebo movement in the Korean Peninsula can be correlated with the early Yanshanian movement (the A episode) in eastern China, although the Daebo movement was slightly older than the early Yanshanian movement. This study considers that the Jurassic granitoids and the Honam shear zone are possibly products of the Paleo-Pacific subduction during Jurassic period. However, the Jurassic granitoids in the Korean Peninsula and east China have different spatial-temporal zonation features from the Paleo-Pacific subdution model, which provides a sample for further understanding the tectonics of ocean-land and deep shallow interactions of the Earth. We shall keep reporting our new study results.

Different Configurations of Interannual Variability of the Western North Pacific Subtropical High and East Asian Westerly Jet in Summer

This study investigates the circulation and precipitation anomalies associated with different configurations of the western North Pacific subtropical high (WNPSH) and the East Asian westerly jet (EAJ) in summer on interannual timescales. The in-phase configuration of the WNPSH and EAJ is characterized by the westward (eastward) extension of the WNPSH and the southward (northward) shift of the EAJ, which is consistent with the general correspondence between their variations. The out-of-phase configuration includes the residual cases. We find that the in-phase configuration manifests itself as a typical meridional teleconnection. For instance, there is an anticyclonic (cyclonic) anomaly over the tropical western North Pacific and a cyclonic (anticyclonic) anomaly over the mid-latitudes of East Asia in the lower troposphere. These circulation anomalies are more conducive to rainfall anomalies over the Yangtze River basin and south Japan than are the individual WNPSH or EAJ. By contrast, for the out-of-phase configuration, the mid-latitude cyclonic (anticyclonic) anomaly is absent, and the lower-tropospheric circulation anomalies feature an anticyclonic (cyclonic) anomaly with a large meridional extension. Correspondingly, significant rainfall anomalies move northward to North China and the northern Korean Peninsula. Further results indicate that the out-of-phase configuration is associated with the developing phase of ENSO, with strong and significant sea surface temperature (SST) anomalies in the tropical central and eastern Pacific which occur simultaneously during summer and persist into the following winter. This is sharply different from the in-phase configuration, for which the tropical SSTs are not a necessity.

Properties of three seismic events in September 2017 in the northern Korean Peninsula from moment tensor inversion

Moment tensor inversion is conducted to characterize the source properties of the September 3, M6.3, the September 3, M4.6, and the September 23, M3.4 seismic events occurred in 2017 in the nuclear test site of DPRK. To overcome the difficulties in the comparison, the inversion uses the same stations, the same structural model, the same algorithm, and nearly the same filters in the processing of waveforms. It is shown that the M6.3 event is with predominant explosion component, the M4.6 event is with predominant implosion component, while the M3.4 event is with a predominant double couple component (~74%) and a secondary explosion component (~25%). The three seismic events are with a similar centroid depth. The double couple component of the M3.4 event shows a normal fault striking northeastward.

Rayleigh Wave Group Velocities with an Enhanced Resolution in the Northern Korean Peninsula

Using a method suggested by Yanovskaya, we obtained Rayleigh wave group velocities with a resolution of 1.0o ×1.0o in a period range between 10 and 80 s in and around the Korean peninsula. Both regional and distant earthquake data sets were used together in analysis of group velocities. The resolution of the group velocity maps has been remarkably enhanced by the method, especially in the sparse/non-station region in the northern Korean peninsula. Some qualitative geophysical information was inferred from the group velocity maps. In the East Sea, the slow group velocities at periods longer than 40 s suggest the existence of an oceanic lithosphere at depths of 50-70 km, assuming 4 km/s of S wave velocity at a period of 40 s. On the other hand, a thick lithosphere can be inferred in the continental area from the fast group velocities at periods longer than 50 s. For most periods, the group velocities change rapidly over a short distance of about 200 km across the eastern coast of Korean peninsula, which may suggest a rapid change in the thickness of lithosphere in this area.

A 258-year reconstruction of precipitation for southern Northeast China and the northern Korean peninsula

We present a well-verified precipitation reconstruction (r = 0.612, p < 0.01), spanning 1741 to 1998, for a relatively humid monsoon region from southern Northeast China and the northern Korean peninsula, based on tree rings from Chinese pine and Korean pine. We then investigate the variability of the reconstruction, and identify the leading rainfall patterns and regional dryness and wetness modes during the latest 2.5 centuries. This reconstruction shows that three persistent dry decades occurred during the 1840s, 1910s and 1850s and the three wettest decades occurred during the 1770s, 1820s and 1930s. The five years with lowest rainfall were 1759, 1917, 1841, 1747 and 1839, and 1770, 1938, 1819, 1941 and 1822 were the five years with highest rainfall, respectively. As indicated by the spatial correlation patterns, the reconstruction also exhibits regional characteristics. The variation of reconstructed rainfall significantly corresponds to East Asian monsoon.

Provenance variations in the Holocene deposits from the southern Yellow Sea: Clay mineralogy evidence

We present a provenance study of two cores (YSC-1 and YSC-4) from the Central Yellow Sea Mud (CYSM) to investigate the source and transport processes of clay minerals during the Holocene. Clay mineral assemblages of Cores YSC-1 and YSC-4 mainly consist of illite, followed by chlorite and kaolinite, and scarce smectite. Combined with other published data, it is found that the fine sediments in the CYSM are most likely a mixing product of the Changjiang and Korean Peninsula small rivers sediments. In contrast, the influence of Huanghe sediments is rather limited and only appears in the bottom part of Core YSC-1. Decreased contribution of terrigenous supply from the Changjiang to the CYSM since 6.4ka may be related to the formation of modern ocean circulation pattern. After 6.4ka, the finer sediments of Taedong and Chongchon Rivers from the northern Korean Peninsula are dominated in the CYSM. The oceanic fronts likely prevent both the suspended sediments of the west (modern and older Huanghe) and east (southern Korean Peninsula small rivers) sides from dispersing into the central Yellow Sea. Our results thus highlight the highly complex nature of sediment source and dispersal pattern in the Yellow Sea during the Holocene. More detailed studies are needed to better understand the sediment source-to-sink history of Yellow Sea.

Vegetation of the northern Korean Peninsula: classification, ecology and distribution

Vegetation of the northern Korean Peninsula: classification, ecology and distribution

Climate oscillation during the Quaternary associated with landscape heterogeneity promoted allopatric lineage divergence of a temperate treeKalopanax septemlobus(Araliaceae) in East Asia

We investigated the biogeographic history of Kalopanax septemlobus, one of the most widespread temperate tree species in East Asia, using a combined phylogeographic and palaeodistribution modelling approach. Range-wide genetic differentiation at nuclear microsatellites (G'(ST) = 0.709; 2205 samples genotyped at five loci) and chloroplast DNA (G(ST) = 0.697; 576 samples sequenced for 2055 bp at three fragments) was high. A major phylogeographic break in Central China corresponded with those of other temperate species and the spatial delineation of the two temperate forest subkingdoms of East Asia, consistent with the forests having been isolated within both East and West China for multiple glacial-interglacial cycles. Evidence for multiple glacial refugia was found in most of its current range in China, South Japan and the southernmost part of the Korean Peninsula. In contrast, lineage admixture and absence of private alleles and haplotypes in Hokkaido and the northern Korean Peninsula support a postglacial origin of northernmost populations. Although palaeodistribution modelling predicted suitable climate across a land-bridge extending from South Japan to East China during the Last Glacial Maximum, the genetic differentiation of regional populations indicated a limited role of the exposed sea floor as a dispersal corridor at that time. Overall, this study provides evidence that differential impacts of Quaternary climate oscillation associated with landscape heterogeneity have shaped the genetic structure of a wide-ranging temperate tree in East Asia.

Characteristics of mass concentrations depending on synoptic features during airborne dustfall episodes observed at Cheongwon in Korea in 2005

Sandstorms in the desert and loess regions of north China and Mongolia, as well as the associated dustfall episodes on the Korean Peninsula, were monitored in 2005. The ground mass concentrations of PM10 and PM2.5 were analyzed during dustfall episodes at Cheongwon, in central south Korea, based on synoptic features at surface, 850 hPa and 500 hPa levels. A total of seven dustfall episodes lasting eleven days were observed and the mass concentration ratios of PM2.5 and PM10 during dustfall episodes were classified into a severe dustfall episode (SDE) and a moderate dustfall episode (MDE) depending upon two synoptic features. The main synoptic feature was for SDEs, which occurred frequently under a surface anticyclone and cyclone located in the west and east of the Korean Peninsula with large amplitude trough at 500 hPa over the northern Korean Peninsula. The sandstorms at the source headed directly to Korea via a strong N-NW wind without passing through any large cities or industrial areas of east China. The PM10 mass concentration sharply increased during the SDEs; however, the fine aerosol fraction of PM2.5 levels was relatively low with 13.6% of the mass concentration. In a synoptic feature for MDEs, a slow moving cyclone headed to Korea via the industrial areas of northeastern China under a small amplitude trough at a 500 hPa level. A weak anticyclone was also located over China. MDEs showed low mass concentrations of coarse PM10 particles and large fraction of fine PM2.5 particles at 46.3%.

Regional observations of the second North Korean nuclear test on 2009 May 25

SUMMARY The suspicious seismic event that occurred in the northern Korean Peninsula on 2009 May 25 was declared to be the second underground nuclear test (NK2ND) by North Korea. We investigated the characteristics of NK2ND using seismic signals recorded at regional-distance stations in South Korea and China. The Pn/Lg ratios of NK2ND definitely discriminate this event from two nearby natural earthquakes at frequencies above 4 Hz. Full moment tensor inversion of full waveform data shows that NK2ND had a very large isotropic component. Pure isotropic moment tensor inversion also resulted in good recovery of observed waveforms, with clear indication that NK2ND was explosive in origin. The moment magnitude (Mw) from the full moment tensor inversion was estimated to be 4.5 and network-averaged values of 4.6 and 3.6 were calculated for rms mb(Lg) and Ms(VMAX), respectively. Although mb−Ms signature has been considered one of the most reliable discriminants for separating explosions and earthquakes, this signature showed poor discrimination in the case of NK2ND. The Pn/Lg ratios and moment tensor inversion give more reliable evidence than does the mb−Ms for classifying the suspicious event in the northern Korean Peninsula as a possible explosion. The characteristics of NK2ND are also quite similar to those of the first North Korean nuclear test on 2006 October 9.

First Report of Pine Wilt Disease on Pinus koraiensis in Korea.

Pine wilt disease is one of the most important forest tree diseases, especially in the East Asian countries of Japan, China, and Korea. The causal agent, Bursaphelenchus xylophilus (3), is transmitted by the insect vectors, pine sawyer beetles (Monochamus spp.). The vectors mainly attack coniferous trees and the infected trees die within several weeks. In Korea, pine wilt disease was first reported in Busan City in 1988, and now, the damaged area covers 7,820 ha and more than 60 cities in Korea. The main host trees are Pinus densiflora and P. thunbergii, which are the most common pines distributed in Korea. In 2006, however, we found pine wilt disease in a forest of P. koraiensis located in Gwangju City in Gyeonggi Province. Symptoms were systemic and leaves turned brown or yellowish. Wood samples were collected from the affected trees, and nematodes were extracted by a modified Baermann's funnel method. After 24 h, nematodes were collected from wood chips, and morphology was observed with an inverted light microscope (Leica DE/DMI 3000B, Wetzlar, Germany). Morphology was characterized by a typical Aphelenchoid-type esophagus, head constriction, female vulva flap, female tail, and a male spicule shape similar to B. xylophilus. For more accurate identification, DNA was extracted from individual nematodes with a DNeasy Kit (Qiagen, Valencia, CA). The internal transcribed spacers (ITS) 1 and 2 and 5.8S regions were amplified by PCR (1). Sequenced nucleotide information was compared with the sequences of B. xylophilus already reported in GenBank (Accession Nos. AB294736, AB277208, AM 157747, AY 347913, and BXU92464). ITS DNA sequences of the nematode from Korean pine was >99% identical to B. xylophilus in GenBank. The B. xylophilus from Korean pine tree was also successfully cultured in Botrytis cinerea medium and pathogenicity was tested from June to October 2007. More than 95% mortality was observed with the inoculation of 20 replicate 15-year-old trees of P. koraiensis and P. densiflora with 15,000 nematodes per tree. Therefore, we confirmed that pine wilt disease occurred in P. koraiensis in Korea. P. koraiensis is an endemic species in Korea and distribution is limited to the northern Korean Peninsula and some locations in Russia. It has been shown that P. koraiensis is susceptible to the pine wood nematode by an inoculation test in Japan (2); however, to our knowledge, this is the first report of pine wilt disease on P. koraiensis under field conditions in Korea.