Taipei Metropolis Research Articles

Spatiotemporal topology of religious spread in a multi‐religious metropolis: A historical religious profile of Taipei City in Taiwan from 1660 to 2020

AbstractReligious identities play an important role in shaping migrants' experiences. Understanding the spatiotemporal distribution of religions enhances our knowledge of both religious expansion and religious cultures. This paper aims to leverage spatiotemporal analysis to characterise the topology of the spread of multiple religions in the Taipei metropolitan area from 1660 to 2020, including Folk Taoism (853 temples/altars, 55.39%), Christianity (306 churches, 19.87%) and Buddhism (332 temples, 21.56%). Three major factors affecting religious distribution are considered: the year of establishment of religious units (churches, temples or altars), the reclamation year of religious locations, and the economic index of religious sites. The results show that Folk Taoism and Buddhism have a long history of development in early reclamation regions with a hopping expansion pattern. However, Christianity expanded later in the later reclaimed and early reclaimed areas. The Christian religious units have highly concentrated spatial patterns and are located in the higher‐income districts, centralised in the core regions of the Taipei metropolis. Modern forms of highly institutionalised religion, such as Buddhism and Christianity, are more prevalent in the relatively higher‐income, later‐cultivated areas, which provide richer social resources for development. Folk Taoism, as a traditional religion, is maintained and developed by local communities. This macroscopic analysis helps to (1) identify the exact chronology of different growth waves and explain them in a historical context, and (2) elucidate the spatial distribution differences between institutionalised religions and folk religion. Our research shows the evolution of religious landscapes from an undeveloped city to a developed city, offering valuable insights for geographical and religious studies, and enhancing understanding of diffused and institutionalised religious expansion.

Vertical characteristics and predictive model development of bioaerosols in Taipei Metropolis

Vertical characteristics and predictive model development of bioaerosols in Taipei Metropolis

Influence of the Geographic Channel Effect on PM2.5 Concentrations over the Taipei Basin in Relation to Continental High-Pressure Systems during Winter

In addition to the Taiwan Strait, the geographical channel effect (GCE) has been observed in the Taipei Basin during winters. This study explored the potential links amongst GCE phenomena in the basin, fine particulate matter (PM2.5) events, and position of the continental high-pressure system (CHPS). Principal component analysis was applied to classify the CHPS distribution patterns influencing PM2.5 concentrations and meteorological parameters in the Taipei metropolis. In addition, non-parametric Kruskal–Wallis and Dwass–Steel–Critchlow–Fligner tests were applied to compare the parameters amongst distinct groups. Moreover, track analysis was utilised to trace the trajectories of air masses. The merged Dark Target Aerosol Angstrom Exponent (Ocean), Deep Blue Aerosol Angstrom Exponent (Land), and Aerosol Optical Depth (AOD) 3 km (Land and Ocean) of Terra/MODIS and Aqua/MODIS were used to confirm the connection of long-range PM2.5 transport. Two features in the atmospheric environment induce double GCEs: (1) wind direction below 90° in most of the upwind area of the Taisumi and Xindian River Basins; (2) CHPS centres moved across 110° E. Double GCEs can reduce the magnitude of PM2.5 air pollution and shape the distribution of PM2.5; however, they cannot prevent PM2.5 events.

Urban Air Pollution and Subclinical Atherosclerosis in Adolescents and Young Adults

PurposeThe contribution of air pollution to subclinical atherosclerosis in a young population remains limited. This study aimed to assess whether long-term exposure to urban air pollutants increases carotid intima-media thickness (CIMT) in adolescents and young adults. MethodsThis study included 789 subjects between the ages of 12 and 30 years who lived in the Taipei metropolis from a cohort of young Taiwanese individuals. Residential addresses were geocoded, and annual average concentrations of particulate matter (PM) of different diameters, e.g., PM10, PM2.5–10, PM2.5, and nitrogen oxides (NOX), were assessed using land use regression models. The generalized least squares strategy with error term to consider the cluster effect of living addresses between individuals was used to examine the associations between urban air pollution and CIMTs. ResultsAfter adjusting for potential confounders, we found that interquartile range increases in PM2.5 (8.2 μg/m3) and NOX (17.5 μg/m3) were associated with 0.46% (95% CI: 0.02–0.90) and 1.00% (95% CI: 0.10–1.91) higher CIMTs, respectively. Stratified analyses showed that the relationships between CIMT and PM2.5 and NOX were more evident in subjects who were 18 years or older, female, nonsmoking, nonhypertensive, and nonhyperglycemic than in their respective counterparts. DiscussionLong-term exposure to PM2.5 and NOX is associated with subclinical atherosclerosis in a young population. Age, sex, and health status may influence the vulnerability of air pollution-associated subclinical atherosclerosis.

Urban Fine Particulate Matter and Elements Associated with Subclinical Atherosclerosis in Adolescents and Young Adults.

The relationships between the elemental constituents of PM2.5 and atherosclerosis remain limited, especially in young populations. This study included 755 subjects aged 12-30 years in the Taipei metropolis. A land use regression model was used to estimate residential annual mean concentrations of PM2.5 and eight elemental constituents. We evaluated the percent differences in carotid intima-media thickness (CIMT) with PM2.5 and elemental constituent exposures by linear regressions. Interquartile range increments for PM2.5 (4.5 μg/m3), sulfur (108.6 ng/m3), manganese (2.0 ng/m3), iron (34.5 ng/m3), copper (3.6 ng/m3), and zinc (20.7 ng/m3) were found to associate with 0.92% (95% confidence interval (CI): 0.17-1.66), 0.51% (0.02-1.00), 0.36% (0.05-0.67), 0.98% (0.15-1.82), 0.74% (0.01-1.48), and 1.20% (0.33-2.08) higher CIMTs, respectively. Factor analysis identified four air pollution source-related factors, and the factors interpreted as traffic and industry sources were associated with higher CIMTs. Stratified analyses showed the estimates were more evident in subjects who were ≥18 years old, females, or who had lower household income. Our study results provide new insight into the impacts of source-specific air pollution, and future research on source-specific air pollution effects in young populations, especially in vulnerable subpopulations, is warranted.

Poor Visibility in Winter Due to Synergistic Effect Related to Fine Particulate Matter and Relative Humidity in the Taipei Metropolis, Taiwan

Visibility is important because it influences transportation safety. This study examined the relationships among sea–land breezes, relative humidity (RH), and the urban heat island (UHI) effect. The study also sought to understand how the synergistic effects of fine particulate matter (PM2.5) and RH influence visibility. Hourly meteorological, PM2.5 concentration, and visibility data from 2016 to 2019 were obtained from government-owned stations. This study used quadratic equations, exponential functions, and multi-regression models, along with a comparison test, to analyse the relationships between these variables. While sea breezes alone cannot explain the presence of PM2.5, UHI circulation coupled with sea breezes during winter can promote the accumulation of PM2.5. The synergistic effects of RH, PM2,5, and aerosol hygroscopicity exist in synoptic patterns type I and type III. PM2.5 was negatively correlated with visibility in the winter, when the RH was 67–95% and the continental cold high-pressure (CCHP) system was over the Asian continent (type I), or when the RH was 49–89% and the CCHP had moved eastward, with its centre located beyond 125° E (type III). The synergistic predictor variable PM2.5×RH was more important than PM2.5 and RH individually in explaining the variation in visibility.

Capital and symbolic power in water quality governance: stakeholder dynamics in managing nonpoint sources pollution

Maintaining quantity and quality is a primary concern in the supply of drinking water. One critical indicator of water quality is nonpoint sources (NPS) pollution. However, persistent risks regarding water quality maintenance have often resulted from compounded social dynamics occurring within and between institutions, while solutions tend to concentrate on scientific/technological treatments. The present study aims to analyse the social dynamics operating within and between such institutions, with a particular focus on the management of NPS pollution that involves the participation of headwater residents. A qualitative case study was conducted on the management of the headwater in Taipei metropolis. The study applied Bourdieu's field theory to understand the mechanism of social interaction and diverse interests among stakeholders. Through in-depth interviews with stakeholders, this research investigated their perceptions regarding various water quality threats and treatments, also mechanisms and gaps in the implementation of NPS pollution-related policies. The study then interpreted emerging issues by considering the stakeholders' various forms of capital input, their strategies in capital exchange and accumulation, as well as the diverse symbolic powers in water quality governance. The research indicates that the ambiguous character of NPS pollution leads to diverse perceptions towards water quality risk, and the ambivalent strategies in negotiation also create barriers to stable stakeholder relationships. Consequently, the research suggests that technocratic-centred governance should also contain sociological perspectives on personal mentality and power dynamic in the society.

Source apportionment of urban PM2.5 using positive matrix factorization with vertically distributed measurements of trace elements and nonpolar organic compounds

There are limited source apportionment studies conducted to assess vertical distributions of fine particulate matter (PM2.5) and its contributing sources in urban regions. Additionally, none of these vertical studies used inorganic and organic tracers simultaneously. The present study aimed to explore the vertical variation of source-specific contributions to PM2.5 by modeling with both inorganic and organic markers in vertically stratified samples in the Taipei metropolis (Taiwan). One hundred and five samples were collected from three floor-levels at one building and analyzed for trace elements and nonpolar organic compounds (NPOCs). Seven source factors, i.e., industrial emission, biomass burning, PAH related, oil combustion, soil dust, traffic related, and environmental tobacco smoke (ETS)/lubricant, were retrieved by positive matrix factorization (PMF). The major contributors, including industrial emission (29%), biomass burning (23%), and oil combustion (22%), could be involved with regional transported aerosols and showed non-significant variation in the vertical distribution. In contrast, both traffic related and ETS/lubricant factors could be the contributors to the statistically significant difference of PM2.5 concentrations between floor-levels.

The role of territorial conflicts in multi-municipal water governance: a case study from Taipei Metropolis

ABSTRACT Multi-municipal water governance, with fragmentation and asymmetry among boundaries and institutions caused by water sharing, can give rise to quarrels among governments. Many related cases worldwide suggest integration and bottom-up participation as solutions for fostering multi-municipal collaboration, although existing power imbalances and competing interests continue to motivate conflicts. The research attempts to provide insights on how territorial conflicts can create barriers to multi-municipal integration. The case study considers the headwater of Taipei Metropolis, located in a rural-urban nexus in Taiwan, which is characterised by disconnected territory and authority. Along with democratisation and urbanisation, conflicts in interests between the headwater municipality, New Taipei City, and the capital downstream, Taipei City, have become more significant. By content and discourse analysis using secondary data and semi-structured interviews, the study identifies critical changes leading to the curious status quo and possible reasons for unresolved conflicts. The configuration of a multi-municipal water-sharing region has mediated inner tensions of territorialisation, which have been stimulated by developmental pressures of a growing entity under changing scalar status in the municipal hierarchy. The research indicates that territorial discourses provide legitimacy for municipal interests, while marking a shift from upstream inequity to downstream water sharing. The case study identifies the role of territorial conflicts and stresses the impacts of municipal competition triggered by scale politics, thereby offering an alternative understanding of conflicts in multi-municipal water governance.

Dense seismic arrays deny a massive magma chamber beneath the Taipei metropolis, Taiwan

Several recent studies suggest that the Tatun Volcano Group (TVG) in the Taipei metropolis of Taiwan is still active with a mappable magma chamber beneath it. Here we report new seismic evidence from dense seismic arrays in northern Taiwan to refute the presence of a massive magma chamber. We investigated two near Taipei earthquakes with focal depths of ~ 140 km. We found that all the waveforms exhibited distinct S waves even when they traversed across the previously postulated magma chamber. Instead, the S-wave shadows found in the previous study may result from seismic waves traveling through a magma diapir above the subducting Philippine Sea Plate offshore northern Taiwan. Moreover, we found the P-wave delay increased with hypocentral distance when the seismic waves propagated through the footwall (west side) of the Shanchiao fault, regardless of whether they traversed across the postulated magma chamber. Our study results also indicate no abnormal attenuation when seismic rays traversed across the postulated magma chamber. Furthermore, the average {Q}_{P}/{Q}_{S} ratio around the TVG is less than 1, which implies that scattering attenuation is dominant. We conclude that a highly fractured rock body is beneath the TVG with a tiny fraction of magma instead of a massive magma chamber. Without sufficient magma supply, the TVG may stay dormant (except for small phreatic eruptions).

Mapping Surface Deformation Over Tatun Volcano Group, Northern Taiwan Using Multitemporal InSAR

The Tatun Volcano Group (TVG) is located at the northern coast of Taiwan Island with only 15 km to the Taipei metropolis. Recent geothermal and geochemical studies suggest that the TVG is dormant-active rather than extinct, implying the eruption potential to devastate the nearby area of 7 million inhabitants. Although some geodetic tools (e.g., global positioning system and precise leveling) have been utilized to analyze the activity associated with volcanism, it is still challenging for conventional interferometric synthetic aperture radar (InSAR) technique to obtain clear ground surface movement at the TVG due to decorrelation and complex atmospheric delay. In this study, we present an improved multi-temporal InSAR (MTInSAR) approach to explore the temporal evolution and spatial extent of displacement at the TVG from 19 L-band ALOS/PALSAR images acquired between 2007 and 2011. Stratified atmospheric delays and orbit error are corrected with a patch-based joint model as different phase components can be separated according to their distinct spatiotemporal characteristics. The spatial deformation patterns indicate an uplift of 10 mm/year at the SW-NE ridge and subsidence with a rate of 10 mm/year at the E-W ridge. The temporal deformation variations at Mt. Chihshin and Huangzuei have high similarity with correlation coefficients of 0.9 above. This indicates that the subsidence at Mts. Chihshin and Huangzuei might be caused by released hydrothermal fluids related to tectono-magmatic activity within the hydrothermal system beneath the TVG.

The capitalization of spatial healthcare accessibility into house prices in Taiwan: an application of spatial quantile regression

Purpose Population ageing is fast becoming a major social concern across the globe. This ageing trend unavoidably fuels elders’ demand for healthcare services. As the main users of health care service, whether the healthcare is geographically approachable in local areas is more imperative to senior residents with restricted mobility. This paper proposes to examine the effect of elders’ healthcare accessibility on property prices of Taipei Metropolis, Taiwan. Design/methodology/approach Luo and Qi’s (2009) enhanced two-step floating catchment area method – taking both healthcare demand and supply into account – was used to measure three types of healthcare services: “physician-to-elder ratio”, “hospital bed-to-elder ratio” and “ambulance-to-elder ratio”. Spatial quantile regression (SQR) model was then used to examine the spatial effect of healthcare accessibility on different property price ranges. Findings The “physician-to-elder ratio” and “hospital bed-to-elder ratio” demonstrated expected consistent positive effects across all quantiles of property prices (p < 0.01) in SQR, and its effects aggravated as the quantiles of property prices rose. The “ambulance-to-elder ratio” demonstrated a non-linear influence on property prices (i.e. a negative effect on lowest quantile prices but a positive on higher quantile prices) possibly due to the semi-obnoxious characteristic of the ambulance. That is, residents living in lower priced neighbourhoods may dislike ambulances’ annoying sound of sirens (i.e. ambulances’ disamenity), while residents living in higher valued neighbourhoods may on the contrary appreciate ambulances’ healthcare services (i.e. amenity). Practical implications These findings are expected to offer some insights for government’s policies in providing elders in their later years with good residential quality and easy access to healthcare resource. Originality/value This paper is one of the few studies that consider the capitalization of the spatial healthcare accessibility to elders into property prices. In this ageing trend across the globe, although all the accessibility to medical resources should be equally critical, the application of spatial quantile regression revealed residents’ inconsistent tendency against semi-obnoxious ambulances. It provides a different perspective in defining the importance of healthcare accessibility in neighbourhoods.

A randomized, double-blind water taste test to evaluate the equivalence of taste between tap water and filtered water in the Taipei metropolis

High water quality and sufficient water availability are the main concerns of water users. Promoting the efficient use of tap water can contribute to sustainable drinking water management and progress towards Sustainable Development Goals. In many metropolises, water suppliers treat municipal water with appropriate treatment processes and well-maintained distribution infrastructure. Under this circumstance, it is acceptable that municipal water can be a source of drinking water. The presence of residual chlorine in tap water, connected to municipal water supply, inactivates pathogenic microorganisms and prevents recontamination. However, adding chlorine to tap water may affect the organoleptic properties of drinking water. On the other hand, the use of point-of-use (POU) water dispensers, which provides an additional treatment step on tap water, is not energy-efficient. A randomized, double-blind water taste test was conducted in the Taipei metropolis to assess whether tap water from public drinking fountains and filtered water from POU water dispensers have similar organoleptic properties. An odds ratio (OR) and the area under the receiver operating characteristic curve (AUC) were used to measure the participants’ ability to distinguish between the two water varieties. A five-region hypothesis test was conducted to test the OR, and a 95% bootstrap confidence interval of the AUC was calculated. The results of the study showed that the 95% five-region confidence interval of OR equal to (0.5, 1.49), and the 95% bootstrap confidence interval of AUC equal to (0.42, 0.56). These results implied that people in the Taipei metropolis could not distinguish between tap water and filtered water. It is recommended that more drinking fountains be installed and maintained fully functional and clean to achieve excellence in tap water access.

Riverfront as a re-territorialising arena of urban governance: Territorialisation and folding of the Xindian River in Taipei metropolis

This paper foregrounds the riverfront as a re-territorialising arena of urban governance. Through a long-term study of the Xindian River in Taipei metropolis, Taiwan, we illustrate how the riverfront can be the key locus where the expansion of the urban frontier is manifested through and intertwines with the transformation of nature. While first interwoven with everyday activities of subsistence, Xindian River was gradually turned into the periphery of the city and then green space for recreation, a process actualised through infrastructure aimed at flood control and waste treatment as well as other informal activities that challenge such measures. We propose that ‘territorialisation’ and ‘folding’ are notions that can grasp asymmetrical relations embedded in the physical landscape. We argue that a riverfront landscape composed by territorialisation and heterogeneous folding reveals that the emergence of a negotiable state–society relationship is pivotal in the production of the urban riverfront of Taipei.

A Major Hydrothermal Reservoir Underneath the Tatun Volcano Group of Taiwan: Clues from a Dense Linear Geophone Array

A dense linear geophone array is deployed across the Tatun volcano group (TVG) at the northern tip of Taiwan, where more than 7 million residents live in the Taipei metropolis. The array is composed of 50 geophones with a station spacing of ~ 200 m in average, and it is designed for striking in the NW–SE direction to record the many earthquakes in eastern Taiwan, where the Philippine Sea plate subducted beneath the Eurasia plate. The detailed examination of felt earthquakes shows consistent P-wave delays are recorded at particular stations of the array. The further forward modeling indicates there is a low-velocity zone (LVZ) at depths between ~ 0.5 and ~ 2.5 km beneath the major fumarole sites. Combining this preliminary result with previous studies including clustering seismicity, volcanic earthquakes, low-resistivity zone, strong degassing processes and shallow velocity structures, we suggest that the LVZ might be associated with the major hydrothermal reservoir at the TVG. The identification of the hydrothermal reservoir by the LVZ not only implies a potential volcanic threat, such as phreatic eruptions, in the future, but also provides the possibility of sustainable geothermal resources for replacing traditional nuclear and fossil fuel power plants. Detailed images of the LVZ and other volcanic structures will be obtained soon when dense geophone arrays with more than 600 geophones are deployed from 2020 to 2022.

Does the school input quality matter to nearby property prices in Taipei metropolis?

PurposeThis paper aims to analyse the spatial effect of school input – “student–teacher ratio” – on property prices in Taipei Metropolis, Taiwan. The falling fertility rate inevitably changes educational system since more less-experienced part-time teachers are hired for the sake of schools’ budget. Hence, in addition to full-time teachers, part-time teachers are included in measuring the student–teacher ratio to see if an increase in part-time teachers, indicating the possible plunge of school quality, may decrease the value of nearby properties.Design/methodology/approachThree types of spatial regressions (including spatial lag, spatial error and SARAR models), which incorporate different kinds of spatial dependencies into hedonic models, are applied to reveal the relationship between two measures of student–teacher ratios and property values.FindingsConventional variables, including housing attributes, demographics and local facilities, demonstrated their consistent and expected influence on property prices. More importantly, the significant “student–teacher ratio 2” (both full-time and part-time teachers) indicated that low-paid, less-experienced and overworked part-time teachers can hardly deliver quality instruction, which inevitably causes harm to school credit and potential buyers’ confidence in valuing neighbouring properties.Practical implicationsFacing the decrease in children and the shrinking budget, the solution to maintain teacher’s quality is to remove the unnecessary administrative chores from full-time teachers and let them do their jobs rather than hiring part-time teachers. Good school input quality should add value to nearby properties, which in return appeals more students to enrol in this school and further elevate schools’ financial burden.Originality/valueThis paper is one of the few studies that consider part-time teachers in capitalising school-input quality into property prices. The increase in part-time teachers, which may lead to an illusion that each student could have higher degree of individual attention from teachers, actually lowers the education quality distributed to all the students. It provides a different perspective in defining the importance of teaching quality to property values in Chinese culture.

Mapping the socio-political landscape of heat mitigation through urban greenspaces: the case of Taipei Metropolis

We assess socio-political challenges for urban heat island (UHI) mitigation in greenspace planning, focusing on Taipei Metropolis, Taiwan. Through analysis of articles from two newspapers, we suggest that attention to greenery and heat tends to reflect immediate weather or planning considerations, and that there is a persistent perception of greenspace as a barrier to economic development. Broad-based, durable rationales extending beyond climate adaptation benefits may be required to sustain support for greenspace planning in Taipei. There is also a need to raise decision makers’ awareness of the specific actions required to realize cooling benefits via greening. We argue that the Taipei case demonstrates the potential for policy messaging based on greenspace functions to attain cross-sectoral buy-in for greenspace development or preservation, but that planners and policymakers must ensure that consensus-based governance actually delivers cooling benefits to citizens. Our results also indicate that greenspace planning policy could more explicitly address community-level greening specifically targeted at cooling or other climate adaptation challenges.

What might ‘just green enough’ urban development mean in the context of climate change adaptation? The case of urban greenspace planning in Taipei Metropolis, Taiwan

This paper argues that climate change adaptation through strategic greenspace planning requires scholars and planners to think differently about what equity means in an urban greenspace context. We use the heat mitigation potential of greenspace and the case of Taipei Metropolis in Taiwan to assess challenges arising from thinking about fairness in terms of distribution of benefits from greenspace functions, as opposed to fairness in greenspace accessibility and availability. Urban greening to foster ‘resilient’ communities arguably deflects from – or even exacerbates – structural causes of vulnerability, with benefits accruing disproportionately to more affluent or empowered groups. Yet the need for practical action on climate threats in cities is urgent, and for heat, strategic greenspace use considered systematically across a city may mitigate effects through the cooling effect of vegetation. The challenge is thus to balance the justice concerns associated with urban greening with this tangible risk reduction potential.We undertake content analysis of articles from two Taiwanese newspapers – the Taipei Times and the China Post – to assess how heat and greenspace issues have been discussed in urban governance debates within Taipei. We suggest change adaptation through urban greening raises three challenges for equity thinking: (a) guiding planning and governance processes with scientific understanding of how greenspace functions are delivered, even in the face of urban development pressures and site-specific controversies; (b) tempering the social cohesion and practical deployment benefits of neighbourhood-level greening with the need for specific understanding at the city-wide level to most effectively realise ecosystem services; and (c) linking targeted adaptation actions with broader rationales for urban greening, whilst not diluting justice concerns. We caution that pragmatism towards all urban climate adaptation via greening as intrinsically ‘good’ must not serve as a blinder to the need for accompanying social policy measures to reduce unequal vulnerability to climate risks.

Shallow crustal velocities and volcanism suggested from ambient noise studies using a dense broadband seismic network in the Tatun Volcano Group of Taiwan

The Tatun Volcano Group (TVG) is situated adjacent to the Taipei metropolis and was active predominantly around 0.8–0.2Ma (Pleistocene). Various recent lines of evidence suggest that the TVG is a potentially active volcano and that future volcanic eruptions cannot be ruled out. Geothermal activities are largely constrained to faults, but the relationship between volcanism and detailed velocity structures is not well understood. We analyzed ambient seismic noise of daily vertical components from 2014 using a dense seismic network of 40 broadband stations. We selected a 0.02° grid spacing to construct 2D and 3D shallow crustal phase velocity maps in the 0.5–3s period band. Two S-wave velocity profiles transect Chishingshan (Mt. CS) in the shallow 3km crust are further derived.The footwall of the Shanchiao Fault is dominated by low velocity, which may relate to Tertiary bedrock buried under andesitic lava flows dozens to hundreds of meters thick. The hanging wall of the Shanchiao Fault is the location of recent major volcanic activities. Low velocity zones in the southeast of Dayoukeng (DYK) may be interpreted as hydrothermal reservoirs or water-saturated Tertiary bedrock related to Cenozoic structures in the shallow crust. High velocities conspicuously dominate the east of the TVG, where the earliest stages of volcanism in the TVG are located, but where surface hydro-geothermal activities were absent in recent times. Between the Shanchiao Fault and Kanchiao Fault high velocities were detected, which converge below Mt. CS and may be related to early stages of magma conduits that gradually consolidated. These two faults may play a significant role with the TVG. The submarine volcanism adjacent to the Keelung coastline also requires further attention.

Earthquake recurrence assessment of the active Shanchiao Fault in northern Taiwan

The Shanchiao Fault is an active normal fault located in the Taipei metropolis, northern Taiwan. Faulting activities have been observed from both the long-term geological data and the short-term GPS surface deformation along the fault. Particularly, with recent studies suggesting the potential of triggering an Mw 7.0-plus earthquake, the Shanchiao Fault is posing a direct seismic threat to the most important, densely populated Taipei metropolitan area in Taiwan. As a result, this study aims to evaluate the earthquake recurrence probability of the Shanchiao Fault, in an attempt to estimate the seismic hazard and help in decision-making for the Taiwan government. Given the capability of capturing the stochastic nature of tectonic stress accumulating, this study used the Brownian model to calculate the earthquake recurrence of the Shanchiao Fault. From the analysis, the recurrence probabilities of the Shanchiao Fault are determined at 8.3 and 17.4% for the next 50 and 100 years, respectively.