Drowned River Valley Research Articles

Mangrove extent reflects estuarine typology and lifecycle events

Ecosystem services provided by mangrove forests are increasingly recognised worldwide. These values have led to numerous ecosystem protection and restoration measures, including recent blue carbon economic incentives to re-establish mangroves at scale. However, our current ability to predict mangrove extent is based mainly on inundation averages (e.g. hydroperiod) or tidal planes of mature mangrove forests. This study investigates the validity of existing methods to accurately predict mangrove extent by comparing the location of existing mangroves at 27 sites (in 23 estuaries in southeast Australia) against commonly used approaches. To this aim, the downslope and upslope surface elevation limits of the mangrove species Avicenna marina were measured on-site using high-resolution RTK-GPS equipment across different estuarine typologies, including drowned river valleys, strong and weakly tidal estuaries, tidal lakes, and intermittently open/closed estuaries. These measurements were analysed against long-term (8–30+ years) tidal records to estimate inundation characteristics within the estuary. Study results indicate that the commonly used tidal plane method for predicting mangrove extent can incorrectly predict vertical extent by over 40 per cent. Likewise, hydroperiod is a poor predictor of extent as similar hydroperiods can be calculated across significantly different estuarine inundation patterns.Interestingly, the results indicate that mangrove elevations and inundation patterns are not uniform within or across estuaries, although there is uniformity across related estuarine typologies. For instance, inundation patterns in drowned river valley estuaries are more consistent (less extreme inundation and exposure events) than in estuaries with a variable tidal range, such as tidal lakes. Ultimately, this study highlights that predictions of mangrove extent should consider estuarine typology, the lifecycle of mangroves, and potential physio-adaptations to changing inundation patterns. Importantly, future tidal conditions may encourage biophysical adaptations in mangroves which may confound the extent of existing predictive techniques.

Regional comparison of the structure of human well-being related to ecosystem services in coastal areas of Japan: possible effect of anxiety unique to the ria coast

People living in coastal areas have the advantage of accessing a high level of ecosystem services, but are also exposed to the dangers inherent in living by the sea in an area prone to natural disasters. To achieve sustainable utilization of the high ecosystem services of coastal areas, establishment of an effective marine policy based on regional characteristics of human–nature interactions is essential. We compared the structure of perceived satisfaction for five components of human well-being (‘Security’, ‘Basic material for a good life’, ‘Good social relations’, ‘Health’, and ‘Freedom of choice and action’) derived from coastal ecosystem services among three sites in Japan (Wakasa, Sanriku, and Shima) that share the same natural and social backgrounds: highly dependent on fisheries industry, located in the same climate regime (temperate zone), and have similar topographical features (ria coast). Structural equation modeling using the results from questionnaire surveys showed that the three sites shared a common basic structure of the interactions among the five components of human well-being. However, the intensity of interactions among components differed among the three sites. Questionnaire surveys on anxiety about natural disasters and future access to marine ecosystem services were simultaneously conducted at the three sites. The site-specific anxieties were responsible for the difference in the interactions among the five components of human well-being. We propose a method that quantitatively evaluates both positive (satisfaction) and negative (anxiety) aspects of respondents’ subjective assessment as a useful tool for understanding the diversity of human–nature interactions caused by the region-specific natural and social backgrounds of coastal areas.

Fish fauna and environmental factors in river estuaries of small and medium-sized rivers on islands significantly influenced by warm currents.

River estuaries are influenced by terrestrial and marine areas, and have a unique environment that is constantly fluctuating. They are also important habitats for biodiversity conservation. Tanegashima Island is significantly influenced by the Kuroshio Current. Although nearby Yakushima Island has been recognized as a World Natural Heritage site and information on many species has been collected, there is little information on species inhabiting the river estuaries of Tanegashima Island. In this study, the river estuarine ichthyofauna of 26 small and medium-sized rivers on Tanegashima Island was surveyed and a total of 2758 individuals of 29 species and one genus belonging to 15 families were collected. The fish fauna of the river estuaries of Tanegashima Island were classified into three groups, namely the river estuaries where coastal terraces are underdeveloped and drowned valleys are formed, the river group where the riverbed gradient at the mouth is high, and other river groups. Environmental factors selected as being important for ordination of fish fauna were the altitude of the headstreams at the watershed scale, the gradient of the river estuarine area, and the presence or absence of rapids in the estuary. The importance of the geohistorical factor of drowned valley formation, in addition to habitat and watershed scale environmental factors, as a factor on river estuarine fish fauna is an important finding for future conservation of local biota diversity.

Urban structure reinforces attitudes towards tsunami evacuation

Evacuation is a critical life-saving action, especially in devastating natural hazards such as near-field tsunamis. However, the development of effective evacuation measures remains challenging to the extent that a successful example has been referred to as a ‘miracle’. Here we show that urban structures have the potential to reinforce attitudes towards evacuation and significantly influence the success of tsunami evacuation. Agent-based evacuation simulations revealed that a distinctive root-like urban structure formed in ria coasts reinforces positive evacuation attitudes by effectively gathering evacuation flows and leads to higher evacuation rates compared to typical grid-like urban structures, which can explain the regional differences in the number of casualties in the 2011 Tohoku tsunami. Although a grid-like structure reinforces negative attitudes under low evacuation tendencies, with leading evacuees, its dense feature helps to propagate positive attitudes and drastically improve evacuation tendencies. These findings pave the way for making successful evacuation inevitable through harmonised urban and evacuation plannings.

Growth Rate Analysis Casuarina equisetifolia of The Case Study Pacitan and Samas Coast Area

The southern coast of Java is an area that is prone to earthquakes and tsunamis because the area is a meeting of the Pacific plate and the Indo-Australian plate meeting the South American continental plate, and the North American plate meeting the Philippine plate. The tsunami disaster can cause significant loss of life and material and cause damage to infrastructure in coastal areas. Casuarina equisetifolia is one type of vegetation that can grow in the southern coastal area of Java, where the coastal morphology is dominated by sand-type material used for protection from wind waves. The primary survey carried out in this study was to obtain the dimensions of coastal forest plants. The results of the Casuarina measurements were the age of 2 to 4 years at the Samas Coast area and 1 to 9 years were made at Teleng Ria Coast area. The analyzing show that increasing logarithmic function of Casuarina the trend of increasing growth of Casuarina tree height. It ages the older the tree height will increase, but this does not apply to the thickness of the tree canopy that grows to the side, because influenced by the position of the shoreline and the plant spacing factor.

Groundwater-surface water exchange affects nitrogen and phosphorus exports from tideless rivers to a ria coast in the sea of Japan

• Groundwater discharge in the downstream area of six tideless rivers was quantified. • Riverbed slope affected the relative contribution of groundwater to surface water. • Groundwater-derived nitrogen and phosphorus were critical for the coastal ecosystem. Groundwater discharge in downstream regions along the river continuum is considered a significant source of water and nutrients. However, the influence of groundwater discharge on the net export flux of surface water and nutrients from tideless rivers to coastal seas has not been thoroughly assessed. We conducted field surveys in the downstream region of six tideless rivers with different watershed properties along the ria coast of Wakasa Bay in the Sea of Japan during the summer. Mass balance models of water, salt, and 222 Rn were constructed to determine groundwater fluxes and associated fluxes of nitrogen and phosphorus. The model revealed that groundwater discharge ranged from 0.08 to 3.89 m d −1 , accounting for 1.3–14.8% of the export flux. This variability among the rivers correlated with the riverbed slope in each river, indicating that the local topographic gradient was a significant factor controlling groundwater-surface water exchange in tideless rivers. Groundwater discharge accounted for 0.8–16.7% of the nitrogen export and 0.9–27.4% of the phosphorus export to coastal seas. We concluded that the groundwater inflow driven by the hydrological and geographic properties of the watershed in the downstream region of tideless rivers was nonnegligible for nutrient dynamics and biological production in the coastal seas.

The Late Quaternary geological history of the upper and central Sydney estuary (Australia)

Sydney estuary, on the east coast of Australia, is a small, drowned river valley with a narrow, sinusoidal channel in the upper reaches; a wide, U-shaped valley with large embayments and tributaries in the central section; and an extensive, more marine lower waterway. The estuary has experienced repeated flooding episodes during Quaternary high sea-level stands, in the absence of neotectonism. The present work considered only the upper and central estuary and therefore, potentially records the highest Quaternary sea-level stands.Valuable information on the geology and sedimentology of Sydney estuary stored in poorly-accessible grey literature has been synthesised and summarised in the current work. The first seismic-stratigraphic model was correlated to borehole data to provide a new Late Quaternary geologic history for the upper and central estuary. Limited absolute geochronological data necessitated reliance on stratigraphic correlation and conformity (uniformitarianism).A basal fluvial unit was overlain by a thick, extensive estuarine sequence, which was followed by fluvial marsh and channel sands and muds with minor wood, gravel and peat. Holocene estuarine muds mantled the upper surface of the estuary. Seismic expression was generally consistent with this lithologic subdivision. The thick estuarine unit acted as an important chronological marker horizon and played a critical role in controlling seismic interpretation throughout this part of the estuary. The paleo-estuarine sequence onlaps the modern shoreline and was most likely deposited during the Last Interglacial highstand (MIS 5.5 at 130–115 kyBP) when relative sea-level in Sydney estuary was between ＋4.5 m to ＋5.5 m above the present surface. The channel and marsh sequences were probably backstepping, progradational units in the upper estuary and possibly bayhead deltaic deposits in the central section. An erosional upper surface, as well as the stratigraphic position of these sequences, suggested deposition during a subsequent Interstadial event, most likely the MIS 5.1 at 82–87 kyBP. The knowledge generated by this study provided useful information for greater understanding of Quaternary estuarine evolution on the Australian east coast and for current and future construction projects in and across the estuary.

The impact of two extensively-modified rivers (Georges and Cooks Rivers) on a receiving basin exhibiting minor ecological risk (Botany Bay) (Australia)

Botany Bay is a large, tide-dominated, drowned river valley on the eastern seaboard of Australia, which was initially planned as the first European settlement in the country. The Georges River has a large catchment (936.5 km 2) and comprises mainly undeveloped parkland (62%), while the Cooks River catchment is small (103 km 2) and substantially modified (90 %). The extent of anthropogenic change and level of ecologic risk were determined for these areas using sedimentary metals as an initial screening assessment of environmental condition of these waterbodies. Cooks River was assessed as one of the most anthropogenically-modified urban rivers on the east coast of Australia with sediments exhibiting severe metals enrichment and moderate ecologic risk. Georges River sediments were highly enriched with moderate to slight ecological risk. Both Georges and Cooks Rivers discharge to Botany Bay, which was mantled in highly metal-enriched sediments, but exhibited only minor ecological risk. These results illustrated an unusual example of an estuary significantly influenced by metal-enriched sediments, but exhibiting minimal ecological risk. This anomaly was due to high anthropogenic-metal concentrations in the fine fraction of surficial sediment, which were considerably diluted by abundant metal-poor coarse material resulting in low total metal concentrations and reduced adverse ecological risk. The low proportion of fine material in surficial sediment was possibly due to increased ambient wave and tidal energy in the bay. Size-normalised metal distributions show distinct dispersion pathways from Cooks and Georges Rivers to the mouth of Botany Bay. Stormwater was a major source of metals to the system, supplemented by leakage from waste dumps and secondary sourcing by remobilisation of enriched-legacy sediments.

First comprehensive ecological checklist of Brachyura in Korea: 1879–2020

The increasing concerns and management needs on marine biodiversity have escalated the requirement for timely documentation of the marine taxa. We first established a comprehensive ecological checklist of Korean Brachyura through a meta-analysis of 74 documents (since the 1870s). A total of 247 species inhabiting the Korean coastal waters are listed with some key ecological information; habitat, substrate, distribution, and delta +. The crabs predominated on Jejudo Island, at the southernmost point of Korea, followed by the South Sea, West Sea, and East Sea. Portunus trituberculatus and Hemigrapsus sanguineus were cosmopolitan species widely distributed across the three seas. Dynamic oceanographic settings of the South Sea, such as archipelago, Rias coast, varied habitats, and (in)direct influence of Kuroshio warm current, seemed to support high crab diversity. The rocky and subtidal habitats represented biodiversity hotspots. The present study would be a useful baseline for gathering further ecological information of globally important marine taxa in Korea and elsewhere.

Impulsive Tsunami and Large Runup Along the Sanriku Coast of Japan Produced by an Inelastic Wedge Deformation Model

AbstractDynamic wedge failure produces short‐wavelength seafloor uplift efficiently with diminishing shallow slip on the plate interface, generating impulsive tsunami. For ria coasts with prevalent small‐wavelength bathymetric and geomorphologic features, such as the Sanriku coast of Japan, impulsive tsunami can be amplified to produce large runup. We model tsunami propagation and runup of the 1896 Sanriku tsunami by using the seafloor deformation from dynamic rupture models of Ma and Nie (2019) for a MW 8 earthquake with inelastic wedge deformation. The nonlinear Boussinesq equation is solved by a nested‐grid finite‐difference method with high‐resolution bathymetry data. We show that an inelastic deformation model with extensive wedge failure produces impulsive tsunami similar to those observed offshore the Sanriku coast in the 2011 Tohoku earthquake and generates large runup remarkably consistent with the 1896 Sanriku tsunami. As an alternative to previous models based solely on fault slip, we suggest that the impulsive tsunami and large runup along the Sanriku coast observed in the 2011 Tohoku earthquake can be explained by inelastic wedge deformation north of 38.5°N.

The Late Quaternary geological history of the lower Sydney estuary (Australia)

Sydney estuary is a dendritic, drowned river valley on the mid-east coast of Australia and comprises an upper and central section of narrow, sinusoidal channels and embayments and a wide, more marine lower estuary. The current work considered only the lower estuary.Minimal research has been undertaken into the structure of the lower Sydney estuary and previous attempts to integrate geologic and geophysical information are limited. The current study combines previously uninterpreted seismic records and poorly-accessible borehole data into a Late Quaternary history of the lower estuary.High-resolution, continuous reflection seismic (212-line km) interpretation matched borehole-based stratigraphy reasonably well. A bedrock paleo-valley deepened from approximately 40 m below present sea level (bpsl) at the Sydney Harbour Bridge (SHB) to > 90 m bpsl at the estuary mouth. Stratigraphy was dominated by two estuarine sequences, which, in the lower part of the estuary comprised mainly fine-grained, organic-rich sediments with peat, that manifest as multiple, strong dark and light-reflectors on seismic. At the SHB, the upper estuarine sequence developed into a transgressive marine to tidal delta deposit. A thin veneer (up to 10 m) of Modern estuarine sands mantled most of the lower estuary. The elevation of the estuarine sediments at approximately present-day levels and at 20 to 30 m bpsl respectively, strongly indicated deposition during periods of high-level marine transgression, i.e. the Last Interglacial (Marine Isotope Stage, MIS 5.5) event at 130 kyPB to 115 kyBP and the Penultimate Interstadial event (MIS 5.1 at 110–80 kyBP), respectively.Late Pleistocene aeolian sands contributed sediment in the south of the estuary, and remobilisation may have dispersed these sediments more widely. Present-day bathymetric features frequently reflected subsurface erosional structures due to starvation of bedload sediment.

Nutrient fluxes from rivers, groundwater, and the ocean into the coastal embayment along the Sanriku ria coast, Japan

AbstractExternal nutrient supply from the land and ocean is crucial for sustaining high primary productivity in coastal seas. Submarine groundwater discharge (SGD) is recognized as one of the most important sources of terrestrial nutrients. However, the relative importance of SGD‐derived nutrients from different sources in coastal ecosystems controlled by offshore exchange has not been well quantified. Here, we assessed water and nutrient budgets in the semi‐enclosed bay along the Sanriku ria coast, where the intrusion of nutrient‐enriched oceanic water is substantial. We conducted seasonal sampling campaigns and monitored the groundwater level throughout the year. Water and nutrient fluxes from fresh groundwater, saline groundwater, river water, and oceanic water were estimated using a hydrological method and radium (Ra) mass balance model. The results indicated that oceanic water was a dominant source, accounting for 99.5%, 86%, 97%, and 84% of the total influx of water, dissolved inorganic nitrogen, dissolved inorganic phosphorus, and dissolved silica, respectively. Although the mean fluxes of land‐derived nutrients were small, the contribution increased to 28–59% in October, when nutrient fluxes of oceanic water weakened. Of the terrestrial sources, SGD dominated (41–94%), particularly saline SGD (>99% of total SGD). We concluded that an efficient supply of the primary limiting nutrient from land to the coastal ecosystem can accelerate coastal primary production during certain seasons, even if oceanic nutrients are typically the dominant source.

Baseline assessment of anthropogenic change and ecological risk of an estuary bordered by an urbanized catchment and a pristine national park (Port Hacking estuary, Australia)

Port Hacking is a tide-dominated, drowned river valley at the southern edge of the Sydney conurbation (Australia) and is bordered by intense urbanization to the north and native bushland in the south. The current work provides a first-time, baseline evaluation of the magnitude of human-induced change and risk posed by sedimentary metals in Port Hacking and catchment. The estuary separates fluvial and estuarine sediment enriched in metals exhibiting moderate ecological risk from sediments with minimal anthropogenic change and no biological risk. A full set of baseline data is provided in support of new monitoring of recent and future anthropogenic impacts on the system.

Does trace fossil size correspond with burrower population density? An example from the modern counterpart of the trace fossil Bichordites

The trace fossil Bichordites appears as an intrastratal burrow and occurs in shallow-marine deposits. Its modern counterpart is the burrow produced by the spatangoid echinoid Echinocardium cordatum, found in shallow-marine regions. The relationship between burrow size and tracemaker population density was studied in the modern, subtidal, sandy deposits of a ria coast in the northeastern Japan. Burrow size decreases with increasing population density in the modern counterpart, suggesting that trace fossil size in Bichordites can be used as a proxy to quantify tracemaker population density at the time of trace formation. However, the factors that control burrow size are unclear and warrant further investigation.

Estuarine-terrestrial habitat gradients enhance nursery function for resident and transient fishes in the San Francisco Estuary

Nursery functions of US West Coast drowned river valley estuaries are not well understood. Using long-term fish-monitoring data (1995-2017) in Suisun Marsh, San Francisco Estuary, California, USA, we examined spatial and temporal trends in abundance and apparent growth of fishes with diverse life-history types. Focal species were Sacramento splittail Pogonichthys macrolepidotus, striped bass Morone saxatilis, tule perch Hysterocarpus traski, and starry flounder Platichthys stellatus, which collectively represented 55% of total catch (n = 140092). We identified keystone habitat patches that functioned as nursery hotspots during the peak young-of-the-year recruitment window. Deep, flow-through sloughs close to the open estuary were important nursery habitats for the marine transient starry flounder. In contrast, splittail and striped bass mostly migrated through such corridors to rear in shallow, dead-end sloughs bisecting tidal marsh plains, managed tidal ponds, and uplands. Tule perch were concentrated in shallow, interior sloughs, reflecting their resident life-history type and adaptations to variable conditions in a small home range. Interactions among freshwater flows and stationary habitat features (e.g. channel depth, land-to-open-water ratio) were related to fish abundance; however, species and age classes differed in their relationships to these interactions, suggesting a mechanism for habitat partitioning in space and time. Overall, we inferred that habitat connectivity—longitudinal, lateral, and vertical—along the estuarine-terrestrial gradient was a driver of fish species diversity and productivity. Consideration of seascape-landscape dynamics across multiple spatial and temporal scales in estuaries should help maintain or increase fish populations and ecological resilience in the face of rising sea levels and other environmental stressors.

Estuarine foraminifera from South West England: impact of metal pollution in a mining heritage area

The southern coastline of SW England is characterized by a number of drowned river valleys (known locally as rias) that contain a range of important estuarine environments including saltmarsh, mud flats, sea grass meadows and open marine sands. All of these ‘rias’ drain catchments with Devonian and Carboniferous rocks that were intruded by granite during the Variscan Orogeny and which were mineralized at that time. The Cornwall and West Devon Mining Heritage UNESCO World Heritage Site records the exploitation of these minerals since Roman times, though mining ceased in the twentieth century. All these mineralized rocks, mining waste and the occasional ‘flood’ of old mine workings have contaminated the estuaries with Cu, Zn, Sn, As, Cr, Hg, Ag, etc., which, in many places, may have left a record of foraminifera with test abnormalities. Since 1973, in a series of student-led projects, the estuaries of the region have been studied for their foraminiferal assemblages, sometimes including sampling strategies that meant monthly, or 3-monthly, suites of samples being collected. The Fal Estuary is one of the largest and most complex of the ‘rias’ and, while draining mineralized areas, also suffered a major release of acidic mine waste during a flood in January 1992. Recovery from that ‘event’ showed that the total absence of foraminifera began to recover within 2 years and assemblages have now returned to pre-incident levels, though still recording malformed individuals. This re-colonization is probably the result of propagule dispersion from more open waters of the Fal Estuary.

Tsunami Modelling with Static and Dynamic Tides in Drowned River Valleys with Morphological Constrictions

Tsunami modelling is widely used to estimate the potential impacts of tsunamis. Models require a tide input, which can be either static, representing a specific tide level, such as Highest Astronomic Tide or dynamic, which represents a moving tide level. Although commonly used, static tide inputs do not account for tsunami–tide interactions, which are known to be non-linear and more significant in estuaries when compared to the open coast. To demonstrate the differences between tsunami models using static or dynamic tide inputs, a series of models were carried out for two New South Wales estuaries, Sydney harbour and port hacking. Model boundary conditions phased a MW 9.0 Puysegur source tsunami with multiple tide scenarios. Fourteen distinct scenarios with dynamic tides were created by phasing the largest tsunami wave peak at regular intervals across the tidal range. For comparison, static tide models were run using equivalent tide levels. The situations where static tide models provide results comparable or more conservative than dynamic tide models are for the first 1–2 h after tsunami arrival, at high tides, and when compared to dynamic falling tides at the same tide level. Differences are most apparent upriver of geomorphological constrictions. The effects of geomorphological constrictions were further examined using idealised model setups with a constriction variable. Results show that constrictions affect downriver maximum water levels, tsunami wave heights, upriver water accumulation and inundation maxima and distributions. These results have implications for estuaries vulnerable to erosion at constriction sites during a tsunami event.

Carbon Budget for a Large Drowned River Valley Estuary Adjacent to an Emerging Megacity (Sydney Harbour)

AbstractAnnual organic and inorganic carbon budgets were constructed for the Sydney Harbour Estuary. Net ecosystem metabolism was the main control on carbon fluxes in the system. Sydney Harbour Estuary was slightly net heterotrophic, which is consistent with a small CO2 emission of 0.8 × 108 mol C yr−1. Terrestrial carbon loads were 70% dissolved inorganic carbon, 21% dissolved organic carbon, and 9% particulate organic carbon. Dissolved inorganic carbon was exported to the ocean (4.19 × 108 mol C yr−1), and an import of organic carbon (1.92 × 108 mol C yr−1) from the ocean was required to balance the budget. Sydney Harbour had high sediment organic carbon burial rates similar to other river valley estuaries including the Hudson River and Chesapeake Bay. Productivity was the main sink of inorganic carbon followed by sediment burial, emissions of CO2 to the atmosphere, and oyster sequestration. This study highlights the importance of determining the sources, sinks, and transformations of all carbon forms in constructing estuarine budgets.

Assessment of Tidal Stream Energy Resources Using a Numerical Model in Southwestern Sea of Korea

In this study, tidal stream energy resources of the Southwestern Sea of Korea were assessed using a numerical model, Modelo Hidrodinâmico (MOHID). This numerical model is based on the finite volume method, which allows numerical experiments on estuaries, coasts, and oceans. For the numerical experiment, we used grid data of at least 90 m resolution by applying bathymetry data created by the Korea Institute of Ocean Science & Technology (KIOST) and FES2012 data as a tidal boundary condition. Strong tidal currents occur in the Southwestern Sea of Korea due to the characteristics of the tidal systems of the West Sea and the South Sea, and the topographical characteristics of a Ria coast. These characteristics were appropriately reproduced by the numerical experiment. Accordingly, the average and maximum tidal currents calculated by the numerical model were used in the assessment. Two regions, Jangjuk and Maenggol-Geocha, were selected as the candidate areas for tidal stream energy development. In addition, the amounts of tidal stream energy resources were evaluated using geographical information system-based spatial analysis by applying the tidal current, depth data, and area of each region. The resource amounts were estimated to be 4,841 MW, with 5,743 tidal stream energy converters (TECs) for Jangjuk, and 3,497 MW, with 3,676 TECs for Maenggol-Geocha.

Influence of Elevation Data Resolution on Tsunami Loss Estimation and Insurance Rate-Making

Tsunamis triggered by large offshore earthquakes are devastating, and buildings located near the coast experience damage and loss due to such extreme events. In evaluating regional tsunami impact via numerical tsunami simulations, it is important to pay close attention to local geographical features represented by a digital elevation model (DEM), because tsunami loss estimation is sensitive to its quality and resolution. This study investigates the influence of elevation data resolution on tsunami loss estimation at different scales by comparing tsunami risk results using DEMs of four resolutions (i.e. 10-m, 50-m, 150-m, and 450-m). Using stochastic tsunami modelling, a case study is carried out by focusing on the Tohoku region in Japan to investigate the influence of DEM resolution on tsunami loss estimation considering the effect of location attributes (i.e. coastal topography, distance from the coast, and land elevation) for two building portfolios on plain coast and ria coast. The results indicate the significance of DEM resolution for local tsunami loss estimations at different locations. The local tsunami risk is closely related to the building location, and the increase of distance from the coast and/or land elevation dramatically reduces the local tsunami risk. The investigations extend discussions regarding the calculations of pure insurance premium rate for tsunami loss coverage depending upon structural attributes and location attributes.