Adam D Switzer

Nanyang Technological University | ntu · Asian School of the Environment

Seaports are vulnerable to extreme sea level events. Beyond physical damage, any port inoperability affects trade flows in and out of the affected port and disrupts shipping routes connected to it, which then propagates throughout the port network. Here, we propose an approach to assessing tsunami risk to ports and the global port network. We lever...

The northern coast of the South China Sea (SCS) is a densely populated and economically important area. Despite the absence of any tsunamigenic events in the last century in this region, their occurrence on a much longer timescale remains largely unknown. Given the catastrophic consequences a potential tsunami event could bring, we aim to bridge th...

Tide–surge interaction plays a substantial role in determining the characteristics of coastal water levels over shallow regions. We study the tide–surge interaction observed at seven tide gauges along Singapore and the east coast of Peninsular Malaysia, focusing on the timing of extreme non-tidal residuals relative to tidal high water. We propose a...

The most prominent abrupt climate event during the Holocene, the ‘8.2 ka event’, was characterized by severe cooling at high northern latitudes causing diverse hydroclimate shifts globally. A precise understanding of the hydroclimate response of the Indo-Pacific Warm Pool (IPWP) region to the 8.2 ka cooling, remains elusive. Here we present sub-cen...

Instrumental sea-level records are insufficient to understand the response of sea-level changes to global temperature on centennial timescales. Sea-level histories spanning at least the Common Era have not been widely studied in Southeast Asia. This period is crucial for providing a pre-industrial context to understand sea-level change with climate...

We examined how variations in the horizontal resolution of bathymetry influence the behavior of modeled tsunamis at shallow depths nearshore. This was done using the Cornell Multi-grid Coupled Tsunami Model (COMCOT) to simulate tsunamis with resampled bathymetric data at resolutions of 5, 10, 20, 30, 40, 50, 100, 200, and 300 meters, derived from 1...

Coastal currents significantly impact port activities, coastal landform morphodynamics, and ecosystem functioning. It is therefore necessary to understand the physical characteristics and natural variability of these currents within coastal settings. Traditional methods, such as harmonic analysis, assume stationarity of tide-driven currents and may...

Traditional approaches to coastal defence often struggle to reduce the risks of accelerated climate change. Incorporating nature-based components into coastal defences may enhance adaptation to climate change with added benefits, but we need to compare their performance against conventional hard measures. We conduct a meta-analysis that compares th...

Submarine volcanism makes up approximately 85 % of volcanism that occurs on Earth, and its eruptions have the potential to cause several hazards including ash dispersal, pumice rafts, pyroclastic density currents, sector collapses, and tsunamis. Recent examples include the eruptions in Japan and in the Kingdom of Tonga in 2021 and 2022 respectively...

Volcanic meteo-tsunamis, though rare, can pose significant threats to people, as exemplified by the 2022 Hunga Tonga – Hunga Ha’apai (HT-HH) eruption in the SW Pacific. While various studies have delved into the complexities of such phenomena, none have explored analogous scenarios in regions with potential occurrence of large eruptions near or und...

Coastal lowlands provide livelihood to˜¼ of the world's population. In the current context of rapid sea-level rise, delta landscapes are susceptible to marine transgression and land loss. The palaeo-geographic evolution of deltas provides insight on the specific processes (sea-level rise, climate, tectonics and fluvial dynamics) that shape each of...

Tide-surge interaction (TSI) plays a substantial role in determining the characteristics of surges over shallow regions. A variety of approaches have been used to study TSI globally, and TSI have been found to occur in Singapore and the east coast of Peninsular Malaysia. However, the characteristics of TSI in Singapore and the east coast of Peninsu...

The Palu Formation, previously known as the Celebes Molasse in the Palu area, is understudied and was previously considered to be associated with the Pliocene collision between an Australian-derived micro-continent – Banggai Sula– and the eastern margin of Sundaland (West Sulawesi). Here, we present sedimentological, heavy mineral, and zircon geoch...

Coastal currents significantly impact port activities, coastal landform morphodynamics and ecosystem functioning. It is therefore necessary to understand the physical characteristics and natural variability of these currents within coastal settings. Traditional methods such as harmonic analysis assume stationarity of tide-driven currents and thus m...

Typhoons are destructive multi-hazard events. To assess the relationship between typhoon intensity and agricultural loss, there is a need for accurate and standardized information on loss and damage, which is currently lacking. To address this, a database for Vietnam and the Philippines was created to provide aggregated information on the magnitude...

Sand is a vital ingredient for modern structures and to meet demand, a substantial volume of sand is extracted illegally from riverbeds globally. The Vietnamese Mekong Delta is one of the largest delta in Asia and it has a long history of riverbed sand mining. We quantified the illegal sand mining rate in this major sand mining hotspot, as the diff...

Rapid urbanization has dramatically increased the demand for river sand, leading to soaring sand extraction rates that often exceed natural replenishment in many rivers globally. However, our understanding of the geomorphic and social-ecological impacts arising from Sand Mining (SM) remains limited, primarily due to insufficient data on sand extrac...

Rapid urbanization has dramatically increased the demand for river sand, leading to soaring sand extraction rates that often exceed natural replenishment in many rivers globally. However, our understanding of the geomorphic and social-ecological impacts arising from Sand Mining (SM) remains limited, primarily due to insufficient data on sand extrac...

The mid-Holocene sea-level highstand refers to higher-than-present relative sea levels (RSLs) in far-field regions between 7000 and 4000 years ago because of equatorial ocean syphoning and continental levering. But the timing, magnitude, and spatial variability of the highstand are uncertain and the highstand parameterization in Glacial Isostatic A...

The deceleration of early to mid-Holocene (10–7 cal. ka BP) relative sea-level rise (RSLR) played a key role in transforming coastal systems from estuaries to deltas. Palaeoenvironmental reconstruction of coastal evolution provide case studies that can help project the response of modern coastal systems to future RSLR. The response of deltas to fut...

In the last two decades, several devastating wave-induced events such as the 2004 Indian Ocean tsunami, 2011 Tohoku tsunami and the 2018 Palu tsunami, demonstrated the need for reliable information on the magnitude and recurrence interval of such events. Sediment archives are a major source of data on extreme palaeoenvironmental events. However, de...

The mid-Holocene sea-level highstand refers to the development of higher-than-present relative sea levels (RSLs) in far-field regions between 7,000 and 4,000 years ago because of equatorial ocean syphoning and continental levering. The timing, magnitude and spatial variability of the highstand are uncertain and the highstand parameterization in Gla...

Low elevation equatorial and tropical coastal regions are highly vulnerable to sea level rise. Here we provide probability perspectives of future sea level for Singapore using regional geological reconstructions and instrumental records since the last glacial maximum ~21.5 thousand years ago. We quantify magnitudes and rates of sea-level change sho...

Shark Bay Marine Park is a UNESCO World Heritage Property located in a region of marginal tropical cyclone influence. Sustainable management of this unique environment as the climate changes requires a quantified understanding of its vulnerability to natural hazards. Here, we outline a structured analysis of novel historical archive information tha...

Submarine volcanism represents approximately 85% of volcanism taking place on Earth, and submarine eruptions can be particularly hazardous due to their potential to cause large-scale hazards from sector collapses, tsunamis, and ash dispersal. While recent eruptions in the Kingdom of Tonga and Japan have highlighted the significant hazards posed by...

Submarine volcanism makes up approximately 85% of volcanism taking place on Earth, and its eruptions can be particularly hazardous, with the potential to cause large-scale sector collapse of the volcanic edifice, tsunamis, and ash dispersal. Recent examples include the eruptions in Japan and in the Kingdom of Tonga in 2021 and 2022 respectively, bu...

We examined how variations in bathymetric resolution affect simulated coastal tsunamis. We used 1-m resolution LiDAR datasets to generate resampled bathymetries with 5, 10, 20, 30, 40, 50, 100, 200, and 300 m resolutions, and added GEBCO data in the comparison. Tsunami waves offshore were generated by setting up an instantaneous rupture sourced fro...

Virtual simulations of future extreme weather events may prove an effective vehicle for climate change risk communication. To test this, we created a 3D virtual simulation of a future tropical cyclone amplified by climate change. Using an experimental framework, we isolated the effect of our simulation on risk perceptions and individual mitigation...

Geological reconstructions of relative sea-level change have been greatly enhanced by continuous high-resolution records with the use of salt-marsh foraminifera due to their relationship with tidal level in modern environments and subsequent preservation of tests in sediments. A detailed understanding of how live foraminifera assemblages compare to...

The identification of tsunami deposits in the geological record remains a challenge because the proxies availabilities are subject to the environment. The proxies may degrade over time and inherently inhibit the robustness of event interpretations. Multi-proxy methods, which leverage on each other's advantage/s and limitation/s, are employed to imp...

Asia has the fastest growing population and economy, but it is also the most disaster‐prone region in the world. Resilience to disaster impacts from natural hazards will be key to the long‐term sustainability of this rapidly growing region. The first step to building resilience is to identify the key threats that this region faces. We describe thes...

Abstract from ICCE 2022

Stratigraphic data from salt marshes provide accurate reconstructions of Holocene relative sea-level (RSL) change and necessary constraints to models of glacial isostatic adjustment (GIA), which is the dominant cause of Late-Holocene RSL rise along the U.S. mid-Atlantic coast. Here, we produce a new Mid- to Late-Holocene RSL record from a salt mars...

Low-lying equatorial islands are susceptible to relative sea level (RSL) rise. Here, we quantify magnitudes and rates of RSL change since the last glacial maximum (LGM) to provide probability perspectives of future sea level. Geological reconstructions and instrumental records from the Sunda Shelf and Singapore show RSL rose ~ 121 m at rates up to...

Collision between Australia and SE Asia began in Sulawesi, the world’s eleventh‐largest island, in the Early Miocene and subsequently Neogene sediments were deposited largely in coastal to shelf environments throughout the island. These sediments have been assigned to the Celebes Molasse, previously considered as a single post‐orogenic unit deposit...

The tsunami hazard posed by the Flores back-arc thrust, which runs along the northern coast of the islands of Bali and Lombok, Indonesia, is poorly studied compared to the Sunda Megathrust, situated ∼250 km to the south of the islands. However, the 2018 Lombok earthquake sequence demonstrated the seismic potential of the western Flores Thrust when...

The most prominent abrupt climate event during the Holocene, the ‘8.2 ka event’, was characterized by severe cooling at high northern latitudes causing diverse hydroclimate shifts globally. To date, a precise understanding of the hydroclimate response of the Indo-Pacific Warm Pool (IPWP) region to abrupt climate changes in the North Atlantic around...

The 109 meridian fault is located in the west of the South China Sea (SCS) connecting to the offshore Red River Shear Zone. Seismic data from the central Vietnamese shelf indicates that many submarine landslides were developed along the steep continental slope in this offshore region. Here, we analyze the potential for such landslides to trigger da...

The river beds of the Mekong Delta are some of the most intensively sand mined places in the world. However, sand mining budgets remain limited to rough and indirect estimates. Here, we provide a first systematic, field-based estimation of the Mekong Delta’s sand mining budget. This budget overcomes the limitations of relying on officially declared...

Information on agriculture-related damage and losses in Asia is under-reported in major multi-peril disaster databases. National disaster databases in some countries may have information on agricultural losses, but this information is not always available. We address this knowledge gap by creating a database of cyclone-induced rice damage from 1970...

Plain Language Summary Long instrumental sea‐level records from tide‐gauges are required to understand regional sea‐level variability, but in most tropical regions tide‐gauge records only began in the latter half of the 20th century. Therefore, there is considerable uncertainty in the regional sea‐level projections in tropical regions, which are ne...

Tropical cyclones have devastating impacts on the environment, economies, and societies and may intensify in the coming decades due to climate change. Stable water isotopes serve as tracers of the hydrological cycle, as isotope fractionation processes leave distinct precipitation isotopic signatures. Here we present a record of daily precipitation...

River deltas are strongly affected by demographic growth and by the intensification of land use. The migration of deltaic coastlines is often rapid, threatening urban settlements, coastal farming, and coastal biotopes. Some deltas benefit from centuries of monitoring, such that the evolution of their coastline is well documented. For most deltas, h...

This work investigated the characteristics of a boulder field on the exposed south east coast of Ludao Island (Green Island) in southern Taiwan. Although the region regularly experiences seasonal Pacific typhoons, fieldwork on Ludao was prompted following the double-strike of Typhoon Tembin in August 2012, which followed an unusual looping track an...

The tsunami hazard posed by the Flores backarc thrust, which runs along the northern coast of the islands of Bali and Lombok, Indonesia, is poorly studied compared to the Sunda megathrust, situated ~250 km to the south of the islands. However, the 2018 Lombok earthquake sequence demonstrated the seismic potential of the western Flores Thrust when a...

The frontal sections of subduction zones are the source of a poorly understood hazard: “tsunami earthquakes,” which generate larger-than-expected tsunamis given their seismic shaking. Slip on frontal thrusts is considered to be the cause of increased wave heights in these earthquakes, but the impact of this mechanism has thus far not been quantifie...

The first formal publication on the geology of Singapore was released in 1976 by the Public Works Department, with an updated version published in 2009 by the Defence Science and Technology Agency (DSTA). This memoir presents a comprehensive revision of the geology of Singapore based largely on information obtained from new borehole cores. Work be...

Devastating disasters that are predicted but ignored are known as Black Elephants—a cross between a Black Swan event and the proverbial elephant in the room. It’s time we acknowledged the looming natural hazard risks that no one wants to talk about.

The mechanism of channel bifurcation in tide-dominated deltas is poorly understood. Here, we evaluate the function of extreme events on the channel bifurcation by examining the lithology, grain size, and organic carbon stable isotope (δ¹³C) composition, as well as the AMS ¹⁴C and OSL ages in two sediment cores (KZ01-A and KZ02) collected close to a...

Typhoon Durian in November 2006 was most notable for a series of devastating lahars that buried communities at the base of Mayon volcano in Bicol, Philippines. Typhoon Durian delivered extreme rainfall that remobilized volcanic debris that caused more than ~1200 deaths and extensive property damage. Although not as deadly as the lahar, Typhoon Duri...