Papers by Montri Choowong
Frontiers in Ecology and Evolution
In Southeast Asian countries, flooding is common and occurs a few weeks after tropical storms. In... more In Southeast Asian countries, flooding is common and occurs a few weeks after tropical storms. In Thailand, the government’s approach to dealing with flooding is focused on the construction of anthropogenic megastructures. The loss of life, property, and ecosystem from flooding still occurs and will likely become increasingly more severe soon due to global climate variation. Here, in this brief report, we show a case study analyzing the cause of unusual flooding that occurred from September to November 2021 during the tropical depression “Dianmu” and the tropical cyclone “Kompasu” that hit the Khorat Plateau, northeastern Thailand. These two tropical storms left behind vast flooded urban and agricultural areas in the upstream part of the Chi River on this, the largest plateau in mainland Southeast Asia. The flood water stagnated for a month and unusually drained downslope in the upstream zone. In this work, a series of free online access satellite images taken by the Sentinel-1 C ba...
Recent development of three-dimensional (3D) seismic datasets enables geologists to visualize and... more Recent development of three-dimensional (3D) seismic datasets enables geologists to visualize and analyze buried land-and sea-scapes revealed by subsurface geophysical data in a manner resembling surface geomorphology. The seismic geomorphology is useful to interpret seismic patterns for geomorphology of a formation, which is similar to using satellite and aerial photos of the Earth's surface. A successful study of seismic geomorphology at the Gulf of Thailand situated within the Sunda shelf reveals the detailed information of paleoenvironment of the Pleistocene to Holocene time. Three sequence boundaries have been observed from the 3D seismic data. These sequence boundaries are related to a change in relative sea level during Pleistocene to Holocene time. The study area is dominated by delta, estuarine and present-day marine environments. The stacked point bar zone has formed in the study area that is potential a reservoir for shallow gas and/or biogenic gas. These results are expected to be a useful tool for petroleum exploration and development in the Gulf of Thailand and adjacent areas.
Quaternary International, 2017
The lack of semi-quantitative paleo data from mainland Southeast Asia, especially from the emerge... more The lack of semi-quantitative paleo data from mainland Southeast Asia, especially from the emergent Sundaland, creates a marked difficulty in following the past Asian monsoon variability. The published pollen records from the adjacent sites to the Sundaland were selected in this study and evaluated for the relationship between taxa and plant functional types (PFTs), and subsequently between PFTs and biome, to eventually reconstruct the semi-quantitative temporal temperature and precipitation profile. In order to comprehend the Asian monsoon modification between 18.5 and 11 ka BP, the derived pollen based temperature and precipitation records were further analyzed together with other selected speleothem records from the Asian monsoon region, with reference to the Greenland and Antarctic ice cores. The warmer temperature in the Southern Hemisphere caused a southward shift of the mean position of the Intertropical Convergent Zone (ITCZ) and weakened the summer monsoon in the Asian monsoon region between 18.5 and 15 ka BP. The Northern Hemisphere temperature played an important role in the Asian monsoon modification between 15 and 13.5 ka BP, where the warmer Northern Hemisphere conditions strengthened the summer monsoon intensity in the Asian monsoon region and moved the mean position of the ITCZ to the north. However, the opposing precipitation pattern between the East and the West Indian Ocean suggested the potential influence of the Walker circulation on the Sundaland climate from 13.5 to 11 ka BP.
Geoheritage
A site with thousands of potholes, locally named “Samphunbok (SPB),” and a giant pedestal (mushro... more A site with thousands of potholes, locally named “Samphunbok (SPB),” and a giant pedestal (mushroom) rock possess a very high geological value. The potholes are being formed on the riverbed of the Mekong River; whereas the giant pedestal rock is the largest on the Khorat Plateau, and is located in Ubon Ratchathani province, north-eastern Thailand. Based on detailed geological, geomorphological, and sedimentological perspectives, this paper presents the geological history of both erosional features for the future promotion of the Global Geopark Network. The giant pedestal rock is likely to be a remnant of degradation and weathering after a regional tectonic event. It is sculptured in the fracture zone of thick sandstone beds after uplifting and folding. No evidence of abrasion by wind was found. The formation of potholes is limited inside the Mekong River bankfull elevation. The appearance of potholes in different levels of the sandstone beds infers their formation in relation to the vertical evolution of the Mekong River. All geological data shown in this paper confirm the rareness of potholes and the giant pedestal rock in terms of how they were sculptured and preserved through time. These erosional features at SPB are discussed and introduced in this paper as a global geological heritage site.
Coastal erosion has been reported to be a severe geological hazard in some coastal areas along th... more Coastal erosion has been reported to be a severe geological hazard in some coastal areas along the Thailand coast. Whether the coastline has really suffered continuous erosion due to a long-term loss of natural sediment from beach zone or it occurred shortly after the human induced activities is still a moot question, which is being debated at present. This paper reviews our findings in a long-term systematic monitoring of beach morphology changes in the areas where severe erosion has been reported. Remotely-sensed data were integrated for evaluating a long-term sediment cycle. For short-term evaluation, we tested the yearly beach profiles and calculated the changes in the coastal area at Pranburi beach ridges plain and at the semi-enclosed bay of Prachuap Khiri Khan, western Thailand. As a result, foreshore profiles at Pranburi area show that the annual depositional rate is more than that of erosion. The northwardly coastal sediment movement at Pranburi area occurs only in rainy season and a yearly balance of sediment here shows a little change in sediment gained and lost. The Prachuap Khiri Khan Bay is in a long-term equilibrium. We conclude in general that a long-term sediment dynamics along both coastal segments are stable, but contain a complexity due to a local difference in shoreface configuration. Our result proves that both long-term and short-term systematic approaches in analyzing coastal sediment balance are essential to understand better the dynamics of natural sediment movement that may or may not be due to erosion.
Washover sedimentation resulting from modern typhoon strikes on the Gulf of Thailand coast forms ... more Washover sedimentation resulting from modern typhoon strikes on the Gulf of Thailand coast forms anomalous sand layers in low-energy coastal environments including marshes, ponds and swales. The primary diagnostic for recognizing prehistoric typhoon-deposited sand layers in the geologic record are sharp upper and lower contacts between coarser-grained transported sand layers and finer-grained in-situ sediments. In this first paleotempestology study in Thailand, cores from two low-energy settings on the Gulf of Thailand coast - a coastal marsh near Cha-am and beach ridge plain swales near Kui Buri - reveal geologic evidence of up to 19 typhoon strikes within the last 8000 years. The sand layers have sharp upper and lower contacts with enclosing finer sediments. Some sand layers also contain other evidence of a sudden powerful landward-directed surge of ocean water, including gravel-sized clasts, offshore foraminifera, abundant shell fragments, plant debris and mud rip-up clasts. Sand layers record eleven typhoon strikes at Cha-am, ranging in age from AD 1952 to 7575 cal. yr. BP, and eight typhoon strikes at Kui Buri, ranging in age from 4075 to 7740 cal. yr. BP. Bayesian age?depth models, derived from eight AMS radiocarbon dates, suggest that the frequency of typhoon strikes was 2-5 times greater from 3900 to 7800 cal. yr. BP compared to 0-3900 cal. yr. BP. Possible explanations for this variability in the typhoon record are that typhoons were more frequent and/or more intense in Southeast Asia in the mid-Holocene because of climatic changes associated with the Mid-Holocene Warm Period or that the record reflects site sensitivity changes resulting from a mid-Holocene sea-level highstand. The preliminary finding of a possible link between warmer conditions and a greater frequency of intense typhoon strikes could have important societal implications, given possible consequences of ongoing global warming.
The preservation of terrestrial dune field in a tropical region is rare and relies significantly ... more The preservation of terrestrial dune field in a tropical region is rare and relies significantly on the degree of weathering process, humidity and anthropogenic condition. In this paper, we report the remnants of sand dunes that is uncovered from Thungkula Ronghai (TKR) dune field in the southern part of the Khorat Plateau, northeastern Thailand. We reveal, for the first time, the results of systematic geomorphological, sedimentological and chronological analyzes of barchanoid ridges and parabolic dunes found on terraces of the Mun and the Chi Rivers. Interpretation in a series of 1952 aerial photographs, satellite images coupled with Ground Penetrating Radar (GPR) survey, and optically stimulated luminescence (OSL) dating were applied. As a result, we found remnants of mega-barchanoid ridges and isolated parabolic dunes varying in height from 1-2 m with maximum length of 4 km, locally distributed in between terraces of the Mun and Chi Rivers, the middle to eastern part of TKR. Dune...
Frontiers in Earth Science, 2021
Grain size, as one of sedimentological proxies, coupled with a detailed description of the sedime... more Grain size, as one of sedimentological proxies, coupled with a detailed description of the sedimentary structures and luminescence dating were used to unveil the sediment sources and transport process of the Holocene ancient coastal storm events recorded in the beach ridge plain, wet swale and muddy environments at Prachuap Khiri Khan, in the Southern Peninsula of Thailand. In this study, a total of 141 sand samples were collected from the shore-normal ridge-swale topography and analyzed for layers of candidate storm deposits, revealing at least 21 candidate coastal storm events. The grain size distribution of beach sediments was, in general, unimodal, while the candidate storm sediments revealed a mixed combination of multimodal, bimodal and unimodal distributions. Plots of mean grain size against skewness and kurtosis and of skewness against kurtosis could differentiate storm deposits from shore-normal beach sediments. Sedimentary structures preserved in the ancient coastal storm ...
Open Geosciences, 2017
The Khorat Plateau from northeast Thailand, the upstream part of the Mun River flows through clas... more The Khorat Plateau from northeast Thailand, the upstream part of the Mun River flows through clastic sedimentary rocks. A massive amount of sand was transported. We aimed to understand the evolution of fluvial system and to discuss the advantages of two shallow geophysical methods for describing subsurface morphology of modern and paleo-channels. We applied Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) to characterize the lateral, vertical morphological and sedimentary structures of paleo-channels, floodplain and recent point bars. Both methods were interpreted together with on-sites boreholes to describe the physical properties of subsurface sediments. As a result, we concluded that four radar reflection patterns including reflection free, shingled, inclined and hummocky reflections were appropriated to apply as criteria to characterize lateral accretion, the meandering rivers with channel-filled sequence and floodplain were detected from ERT profiles. ...
Boreas, 2017
, X.: Stalagmites from western Thailand: preliminary investigations and challenges for palaeoenvi... more , X.: Stalagmites from western Thailand: preliminary investigations and challenges for palaeoenvironmental research. Boreas.
Environmental Earth Sciences, 2017
In order to develop geomorphic criteria for distinguishing and locating abandoned channels and me... more In order to develop geomorphic criteria for distinguishing and locating abandoned channels and meandered belts, in this paper we examined geomorphologic characteristics from the Mun River, one of the main rivers in the Khorat Plateau, northeastern Thailand. Upstream of Mun River originated at southwestern rim of the Khorat Plateau where the river now cuts through sandstone basement. Meandering process shaped meander from upstream ending at low-lying plain about 30 km downstream from the Mun Bon Dam reservoir, and this process displays given values of geomorphic parameters including sinuosity index (SI), channel width (W) and radius of curvature (Rc). Sinuosity index was calculated to express the sinuosity of the channel. The relationship between W and Rc helps to predict channel stability and also comprehend the possibility of cutoff process. As a result, paleo-and recent flow directions of the Mun River are similar from southwest to northeast. Geomorphic parameters from eight river reaches have changed through time since 1974-2015. Two abandoned channel belts were identified, and they own an average channel width of 35 and 16 m, whereas the Mun River nowadays is of 12.7 m. SI values of two abandoned channel belts are categorized as meandering river system. Relationship between meander migration rate and bend curvature suggests that the Mun River possesses low erosion rate between 0.71 and 2.64 m/ year since 1974 to the present. This rank of Rc/W ratio suggests stable state of river bank migration. Different migration indicates discontinuous meandering process from individual belt. Lateral migration rate was also decreased after Mun Bon Dam was constructed upstream.
Geomorphology, 2009
The 2004 Indian Ocean tsunami devastated the coastal areas along the Andaman western coast of Tha... more The 2004 Indian Ocean tsunami devastated the coastal areas along the Andaman western coast of Thailand and left unique physical evidence of its impact, including the erosional landforms of the pre-tsunami topography. Here we show the results from monitoring the natural recovery of beach areas at Khuk Khak and Bang Niang tidal channels of Khao Lak area, Phang-nga, Thailand. A series of satellite images before and after the tsunami event was employed for calculating the beach area and locating the position of the changed shoreline. Field surveys to follow-up the development of the post-tsunami beach area were conducted from 2005 to 2007 and the yearly beach profile was measured in 2006. As a result, the scoured beach areas where the tidal channel inlets were located underwent continuous recovery. The return of post-tsunami sediments within the beach zone was either achieved by normal wind and wave processes or during the storm surges in the rainy season. Post-2004 beach sediments were derived mainly from near offshore sources. The present situation of the beach zone has almost completed reversion back to the equilibrium stage and this has occurred within 2 years after the tsunami event. We suggest these results provide a better understanding of the geomorphological process involved in beach recovery after severe erosion such as by tsunami events.
Natural …, 2004
... MONTRI CHOOWONG1*, HIROAKI UGAI2, TITIMA CHAROENTITIRAT1, PUNYA CHARUSIRI1, VEEROTE DAORERK1,... more ... MONTRI CHOOWONG1*, HIROAKI UGAI2, TITIMA CHAROENTITIRAT1, PUNYA CHARUSIRI1, VEEROTE DAORERK1, RATTAKORN SONGMUANG1 AND ROTTANA LADACHART3 ... FIGURE 3. Sea-level curves of the Southeast Asian countries (after Choowong, 2002a). ...
Uploads
Papers by Montri Choowong