Geothermal as resource for megacities


 33 Megacities are distributed around the world, a number that will increase to 43 by 2030. Megacities are critical for the world’s economy, however, their management is particularly challenging in terms of transportation, water, waste, sanitation, security, electricity, and environmental impact. The increase of energy demand, in parallel to population growth and climate change, requires investment in sustainable energies. Geothermal energy – differently from solar, wind and hydroelectric is independent from weather conditions. A number of megacities around the world are located in areas with anomalous geothermal gradients, proximal to the margins of tectonic plates. This colocation makes geothermal an attractive resilient, baseload, low-carbon, energy source helping Megacities reduce their environmental impact. In this paper, we discuss the advantages of using geothermal energy, leading the study for the city of Bogotá, and applying the same workflow for Los Angeles and Jakarta. We aim to provoke the inclusion of geothermal in energy policies of other megacities around the world.


Introduction
The 2007 was the year when, for the rst time in human history, the percentage of people living in cities exceeded that of people living in the country (Ritchie and Roser, 2020). Today, > 50% of world's population lives in urban areas, this is forecast to increase to 68% by 2050. Urban centres account for 67-76% of global nal energy consumption of which an estimated 71-76% is fossil fuel derived (Seco et al. 2014).
The associated greenhouse gas emissions (GHG) will grow from 70-80%, of the world's GHG discharges in 2050 (IEA, 2008). By 2050 the energy growth for heating and cooling of buildings could increase between 7-40% based on 2010 statistics (Güneralp et al., 2017). The Urban Heat Island (UHI), effects within mega-urban cities (EPA, 2020) will magnify the issues associated with global warming (Huang et al., 2019). Dealing with these challenges requires careful planning and optimisation of economic resources.
The increasing population in urban areas determined the escalation of megacities (city with a population of > 10 millions). There are 33 megacities around the world, a number that will rise to 43  Northern America, Europe, and Japan used on average, per capita, more than 60 GJ (16.6 MWh) -and up to 100 GJ (27.7 MWh) e.g., Los Angeles and New York (Kennedy et al., 2015). Megacities in other parts of the world are quite often below 20 GJ (5.5 MWh), largely because two thirds of the megacities are in regions with warm climate (37% in the subtropics, 37% in the tropics, and 26% in the temperate zone; Table 2). In temperate climates, the demand of energy increases in cold months for heating. Most cities require cooling, with the energy for air conditioning being largely derived from electricity, hence depending on the available capacity of power generation and the existing grid The implications of global warming combined with seasonal variations and the UHI effect may lead to power shortages if infrastructure/planning is not updated. The impact of the UHI alone reveals that temperatures today in cities can be an estimated 0.5-4 °C above unpopulated areas (EPA, 2020). Simple analysis presented in supplementary tables S1 and S2 suggest that the dominant impact of an average 1.5 °C and 3.0 °C temperature increase, is an increase in power use required for cooling, resulting in an estimated 14% and 22% increase in energy. Megacities in a global warming scenario could see a dramatic increase in cooling needs, which poses a problem regarding planning of new construction and retro-tting. Future buildings may need to be constructed to keep the heat out, rather than in.
In addition to energy demands, climate change may be putting strain on the water supply. Megacities located in the subtropics might experience lower than average precipitation as weather patterns change.
Water resources could be impacted requiring access to future water supplies from desalination or recycling of waste-water, all of which increases the future energy demand. At least 19 of the 30 megacities included in Table 1 obtain more than one third of the water supply from both surrounding areas and surface waters (Keys et al. 2018).
Advances in Conventional, EGS and AGS facilitate the concept of producing, low-carbon, sustainable, electricity adjacent to large population centres. In addition, low-grade heat may be used directly in district heating/cooling and in GSHP decarbonizing heating and cooling needs for individual houses or o ces (Ball, 2021a, b). Furthermore, medium-and low-enthalpy geothermal energy can be used to decrease both operation costs and environmental impact from a broad range of industries including desalination of water, green houses, sh farming, brewing/fermenting, chemical products, automotive and large-scale production industry (Ball, 2021a). The combined approach of geothermal for heating and cooling and for electricity production therefore enables geothermal to decarbonize signi cant amounts of the energy needs especially if it is developed in conjunction with solar Photovoltaics (Solar-PV), wind power and improved insulation technologies for existing and new o ce building and homes.

Colombia and Bogotá
With more than 75% of the population living in urban areas, Colombia is nowadays a highly urbanized country. Colombia's electric energy use per year is estimated to be 1,356 kWh per capita (WD, 2020). In 2018 Colombia had an installed energy capacity of approximately 17,312 MW, 63% of energy is derived from hydroelectric power, 29% from fossil fuels (gas and coal), the rest of the balance is from renewables (wind and solar) and other minor thermal sources (Fitch 2019).
Bogotá has grown to a population of ~ 10,700,000 within an area of ~ 397 km 2 ( Table 1). The development of urban and industrial settlements bene t from a relatively at topography within the broad plateau of the Eastern Cordillera of Colombia. Bogotá has a largely isothermal climate that typically varies from 7 °C to 19 °C, and receives the electricity provided by three biomass, two hydroelectric power and one gas/coal thermoelectric plant. The public transport sector is the highest consumer of energy derived mostly from petroleum products (gasoline and diesel) and subordinately from electricity. Both the industrial and residential sectors consume electricity and natural gas, while the sector for services requires electricity and petroleum products (Pardo Martinez, 2015). The energy consumption of Bogotá city in 2017 reached a total of 9241.5 GWh, representing the 17% of the total electricity of Colombia (UPME, 2018). Droughts recently exposed Bogotá to an interruption of energy supply from its hydroelectric plants. The el Niño event in 2015-2016, caused signi cant drought leading to reductions in power output (Fitch 2019). According to statistics from 2018, energy demand in Colombia increased by 3.3%, reaching a total of 1159 kWh per capita (British Petroleum, 2019), and may grow 2.6% yearly, from 2019-2022 (UPME, 2018). Future growth is being met by an increase in gas, wind and solar projects, resulting in a net decrease in the share of power from hydrothermal plants (Fitch, 2019

California and Los Angeles
The United States of America are the second energy consumer in the world after China, and California -its most populous state -is the second in the country after Texas, in terms of total energy consumption (EIA 2020). The EIA ranks California as the world's fth-largest economy which relies on numerous energyintensive industries. California's population is highly urbanized with 97.8% of the population living in urban setting (RHI, 2020). California's installed electricity capacity is approximately 80,000 MW. In addition California imported 77,229 GWh of electricity in 2019 (Nyberg, 2020). California's residential use, is one of the lowest per capita, in the USA, at 6,684 kWh, compared to an average of 11,888 kWh (EIA, 2009). California's total energy consumption, per capita, is 202 million Btu, again one of the lowest in the USA, in part to its favourable climate (EIA 2020). The Californian energy mix in-state is dominated by natural gas (42.97%), large hydro (16.53%) and nuclear (8.06%). Renewables make up the 32.09% of the energy mix, and is dominated by solar (14.22%), wind (6.82%) and geothermal (5.46%), (Nyberg 2020). In 2019 geothermal energy produced 5.46% of California's in-state generation portfolio (Nyberg 2020). The geothermal installed in California accounts for 91% of the USA's steam-powered capacity, since 2000, however, nearly 90% of the new capacity added uses binary-cycle capacity (Linga, 2020). Importantly in California, since 2016, closed-loop binary geothermal developments have been designated as zero carbon (CARB, 2016).
Los Angeles (LA) metropolitan area has grown to a population of 12,458,000 within an area of ~ 12,562 km 2 ( Table 1). The city of LA is a coastal city, built over a deformed, ~ 9 km deep, sedimentary basin with signi cant oil and gas resources (Bilodeau et al. 2007). Climatically the latitude and geographic location and proximity of coastal mountains give LA a temperate Mediterranean climate. There are no geothermal power plants located within Los Angeles County. Integrated energy systems support LA's energy needs, via an extensive transmission and distribution infrastructure (LADWP, 2017). In 2020, the cities energy mix was derived from 34.1% renewable power, including 8.9% from geothermal resources, 21% coal, 4,1% hydroelectric, 27.2% natural gas, 12.5% from nuclear (LADWP, 2020). In 2019, according to the California Energy Commission, the energy consumption of LA reached 66,118.6 GWh, which corresponds to 46,556.1 GWh non-residential, and 19,562.5 GWh in the residential sector (CEC, 2020). The average LA resident uses about 5,900 kilowatt-hours of electricity per year (LADWP, 2020). Both commuting time and distance to reach the workplace means that the transport sector uses 49% of California end-use energy consumption (EIA, 2017). On the other hand, the industry requires 24.5% of state energy use and represents the second-largest energy consumer. Commercial 12.5%, and residential end-use reaches 14% of total energy consumption (EIA, 2020).
California has one of the most decarbonized energy systems in the USA, as a result of proactive renewable energy policies. Yet, climate impacts such as drought and forest res have highlighted some of the limitations of an energy system that is reliant on intermittent sources such as wind and solar PV.
There are several high-pro le rolling-blackout events in California, highlighting the lack of resilience within the state impacting solar, wind and hydrothermal resources (Clemente, 2016). The LADPW 2017 roadmap for LA's energy resource is strongly aimed at decarbonizing its emissions, and as coal is phased out geothermal, wind and solar are targeted to play a signi cant role.

Indonesia and Jakarta
Indonesia is the most populous country in Southeast Asia and the fourth most populous country in the world. According to IEA (2020), its domestic energy consumption is large, fast-growing, and ine cient due to an inadequate infrastructure and a disperse territory which extend on more than 17,000 islands.
Despite signing the 2015 Paris Agreement, Indonesia is, currently, well off-target to meet the reduction in greenhouse gas emissions (IEA, 2020). Indonesia is a producer of old-style biomass and waste-burn energy for its residential sector, particularly in the distant areas not connected to the country energy grid. The country is using fossil fuels to expand its industrial capabilities and develop its electricity and transportation sectors. Presently, the generation capacity in Indonesia is lower than the demand for electricity, leading to frequent power shortages (Christina, 2019). Indonesia has an estimated 71 GW of installed capacity (IDNF, 2020), however, increased urbanization is contributing to an annual 8-9% increase in energy demand, which is not being met despite 15% of Indonesians not having access to the electric grid (Heggie, 2015). As the country modernises, the per-capita electricity consumption is growing rapidly from 0.2 MWh/capita in 1990 to 1.0 MWh/capita in 2018 (IEA, 2020).
Indonesia is the world's second-largest producer of geothermal energy, with 2,130.7 MW of installed power generation capacity from 16 Geothermal Power Plants. By 2030 the country aims to grow capacity to 8,007.6 MW (Richter, 2020). This still only represents a fraction of the estimated 29 GW of geothermal potential within the country (ADB and WB, 2015). In 2019 the Indonesian energy mix for electricity production was coal 59%, natural gas 20.8%, oil 4.1%, hydroelectric 7.1%, geothermal 4.7%, biofuels 3.6% with wind, solar and waste heat making up the remaining 0.7% (IEA, 2020). Total energy consumption use in Indonesia is dominated by the transport sector, 34%, followed by industry, 34.8% and residential end use 22% (IEA 2020). The rapid growth in the transport sector could be due to the dramatic increase in the number of private vehicles, due to expanding mobility in the middle-class (Deendarlianto et al. 2017).
Today, Jakarta, is reported to have a population of 10,517,000 within an area of 556 km 2 (Table 1). Jakarta is a lowland area, built on an alluvial plain, with a relatively at topography. Jakarta is characterized by a tropical monsoonal climate with a mean temperature variation between 24 °C and 29.5 °C. Jakarta is the most vulnerable region in SE Asia to the impacts of climate change and is vulnerable to oods, landslides, droughts, and sea level rise (Yusuf & Francisco, 2009). Decarbonizing the economy, through renewables energy growth, is critical for Jakarta and Indonesia to develop to energy sovereignty and self-su ciency, as the country drives for modernization and access to electricity for its people (IEA, 2020).

Geothermal system near to Bogota
Bogota is built on a sedimentary succession spanning from marine Mesozoic, continental Cenozoic sedimentary rocks, Plio-Quaternary glacial and uvial deposits lling a late Triassic rift system formed during the break-up of the super continent Pangea (Pindell, 1985). The late Miocene inversion of this basin relates to the exhumation of the Eastern Cordillera that followed the collision of the Panama Arc and more generally to the convergence of the Nazca and Caribbean plates under the South American continent (Pennington, 1981).This process triggered the emplacement of foothill fault systems with trend SSW-NNE, and a long lithospheric fracture -the Caldas Tear -connected to an extinct rift (12 − 9 Ma) namely the Sandra Ridge (Figs. 2 and 3; Londsdale, 2005;) with a trend almost W-E. The kinematics of this fracture is currently evidenced by the presence of a 240 km offset between the subduction seismicity and volcanism (Fig. 3a). Barrera et al. (2018) proposed that the lithospheric tear represents a mechanism for the emplacement of thermal anomalies related to late Miocene to Pliocene magmatic intrusions in the central sector of the Eastern Cordillera basin (

Geothermal system near to Los Angeles
The southern region of California, and the continental borderlands, records a complex geological history that involves notable tectonic features like the Los Angeles Basin (LAB), the Peninsular Ranges (PR), and the California Transverse Ranges (TR). The LAB is an early Miocene pull-apart basin located on the edge of the Paci c Plate, and bounded by the TR and PR, promoting a contrasting structural relief (Fig. 5). The basin forms as part of a distributed transform system, which represents the switch from subduction to a transform-related margin at ~ 8 Ma as subduction diminished (Atwater and Stock 1998). The basement rocks in this region are Mesozoic orogenic, meta-igneous, rocks (Humphreys and Coblentz, 2007). There are several large-scale strike-slip faults within the basin, such as the Newport-Inglewood (NIFZ) and the San Andreas Fault (SAFZ). The regional principal stress eld, in the LAB is orientated north-south indicating the major faults in the basin are, presently, undergoing transpressional deformation (Lund Snee and Zoback, 2020). Tomographic images indicate that the lithosphere is thinned to 40-50 km, in the LAB region, whereas the lithospheric thickness is greater 70-80 km, in the PR and TR regions, (Lekic et al., 2011). Signi cant crustal thinning is observed in the LAB where Moho depths are reported to be as shallowing from 25 to 12 km (Clayton, 2020).
Extension was accompanied by signi cant volcanism in the middle-Miocene along the outer edge of the Inner Borderland (Legg et al., 2004). Recent hydrothermal activity evidences are observed present-day along the TR and PR (Luedke and Smith, 1981). Measurements of 3 He/ 4 He ratio in the Los Angeles Basin suggest that there is a strong mantle contribution of helium from long-lived large strike-slip fault systems which intersect with the mantle (Boles et al., 2015). Present day surface heat ow within the LAB is variable ranging from 63 to 85 mW/m 2 . The variation has been proposed to be related to the combined effects of sedimentation, local structural complexities, or re ecting non-steady-state conditions related to magmatism and/or hydrothermal circulation (Zuza and Cao, 2020).

Geothermal system near to Jakarta
Java is a volcanic island arc in the Indonesian archipelago at the southern margin of the Eurasian plate. Inland, several tectonic features as the Lembang Fault (LF), Kendeng Fault (KF), and Cimandiri Fault (CF), de ne the volcanic arc (Fig. 6). This converging margin forms where the Indo-Australian plate (IAP) is subducting under the Eurasian plate (EAP). Subduction has been continuous throughout the Cenozoic, in the segment that forms the island of Java the subduction is observed to be orthogonal (Clements et

Methodology
The concept of GRB refers to the thermal energy Q stored in a volume V of rock in the subsurface and is usually estimated by means of the volumetric heat in place (VHIP) approach proposed by Mu er and Cataldi (1978). It depends on both thermal rock properties and the distribution of the geothermal gradient.
Although this approach provides a simpli ed general idea of the thermal energy on large scales, large uncertainties remain due to the variability of the medium of variables such as density ρ, porosity Φ, heat capacity C, and temperature contrast (∆T) in the region of interest. This method is based on Eq. (1), where the subscript r refers to rock and w to water: Q= [(1 − Φ) * ρ r * C r + Φ * C w * ρ w ] V*∆T (1) However, determining the potential geothermal power is di cult due to the scarcity of available information, furthermore uncertainties relating to newer AGS techniques and their e ciency at mining heat vs. utilizing hydrothermal waters to extract heat is still open for debate, since commercial developments are still not commonplace. Therefore assessment of a pure-play thermal resource is not included in this analysis.
In the Eastern Cordillera the GRB assessment therefore is based on estimates from O&G wells, and associated spring-waters, we assume a regional play with geothermal gradients between 30-40 °C/km (Fig. 3 Figure 4 shows the results of the estimation of the CDPs and highlight a sur cial indenter of CPDs (< 30 km) coming from the west and located in the middle of the LDSW area. This anomaly may be responsible of the heating of the water springs dislocated along the fault system in the crest of the Eastern Cordillera with trend NNE and their complex intersections.
The same principle that was applied to the Eastern Cordillera and Bogata, was used for the cities of Los Angeles and Jakarta. We simplify the model and hypothesize that -even considering the discrepancy between CPDs estimations -the role of the tectonic features controlling the spring-waters and the area encompassing them are fundamental to de ne the volume of potential reservoir that is storing the thermal energy. Therefore, we assume the elliptical envelope that encompasses the LDSW as the best alternative for a better constraining of the area. While the areas, depth, and thickness of recoverable resources have been assumed according to the regional geology of the three areas, an average porosity of 5%, uid heat capacity of 4000 J/kg ºC, rock heat capacity of 850 J/kg ºC, speci c heat capacity of 920 J/kg °K, and an e ciency as low as 0.1% have been set as general values for the three areas. Table 3 summarizes the main volumetric parameters used for estimating the potential geothermal energy, following the method of Mu er and Cataldi (1978), and Viera and Hamza (2014). In addition based on the regional population statistics compiled in Table 1, and statistics reported in Sect. 2, are used to estimate the power consumed by all inhabitants for these megacities and their metropolitan areas. The results are presented below for each megacity studied:

Bogotá
For Bogata, we estimated the maximum value of recoverable resource within an area of ca. 7500 km 2 . We assumed an average depth of 3 km, a 30 m thick sandstone reservoir (the Eastern Cordillera Basin that is approximately 11 km thick, and hosts at least one regional reservoir unit, the Une Formation; Barrero et al., 2007). Our estimations suggest a rough value of resource of approx. 16,603.1 GWh, corresponding to ~ 1.14 times the energy per capital consumed by all people located in the metropolitan area, as per Table 3.
That means a potential coverage of the total residential demand with this resource. This estimated amount of energy may guarantee enough baseload residential electric resources, solely through the use of geothermal derived electricity. .

Los Angeles
Within the region of Los Angeles, spring-water occurrences cover an area of approx. 9.400 km 2 . Where the CPDs are relatively sur cial, coincides with an area ranging between 15-25 km. As with Bogata, we followed same approach to estimate the maximum recoverable resource, using formula (1). Thereby assuming an average depth of 3 km, one 450 m thick reservoir (half of the thickness than in NW Geysers Geothermal Field area, Antúnez et al., 1994). Our estimations suggest a resource of approx. 312,138.8 GWh, corresponding to approx. 3.75 times the energy per capita consumed by all inhabitants that live in this megacity based on the assumptions made in Table 3.

Jakarta
In the region of Jakarta, the CPDs are reported to be < 25 km deep. The distribution of volcanic cones and spring-water occurrences were taken as criteria for de ning the main area for focusing a detailed geothermal exploration near to Jakarta city. The ellipse envelope that encompasses these features de nes an area of approx. 9.100 km 2 . Using same approach as in previous cases, we assume an average depth of 1.0 km, one 30 m thick reservoir (using similar thickness from the Wayang Windu geothermal eld, West Java, Bogie et al., 2008). The estimations indicate a resource of approx. 20,145.1 GWh, corresponding to 1.92 times the energy per capita consumed by all people that are currently living in this megacity.

Environmental Impacts And Resource Administration
The estimates presented here only represent that for conventional and EGS-types of geothermal exploitation. These estimates already highlight that geothermal derived power can be su cient to decarbonize the present energy needs. In some cases it may also help support and decarbonize the future energy needs resulting from climate change and global warming (Supplementary tables S1 and S2). Importantly, geothermal derived power is not as vulnerable to environmental changes, and, importantly, it provides a low-carbon baseload power.
Advances in geothermal completions utilizing binary, closed-loop or AGS, fully mitigate these environmental issues common with ash-geothermal power plants (Bravi and Basosi, 2014;CARB, 2016;Ball 2021a). While binary, closed-loop developments or AGS can increase the cost level of geothermal development, these newer concepts allow a wider deployment of geothermal energy, for power production and provide long-term cost-e ciencies to regions which prioritise GHG reduction targets (Ball 2021a, b).
Geothermal is a baseload technology which meets signi cant energy resilience needs which wind and solar cannot deliver as intermittent sources. Geothermal power could therefore lead to the closure of coal and gas power (Ball 2021a, b), whereas the preference of the apparently cheaper wind and solar-PV technologies, effectively lock a economies into a carbon based gas or coal infrastructure (Gillingham and Huang, 2018).
Promotion of geothermal systems is sometimes challenged due to the initial high installation costs compared with other energy resources. Although it should be remembered that geothermal offers a baseload power whereas wind and solar-PV are intermittent sources that induce additional costs for storage (e.g. battery) and these intermittent sources also bring instability to the grid, requiring that baseload power-stations (for example gas or coal) be maintained on standby to ramp up and down to meet the gaps in energy supply (Ball 2021b). In future geothermal could also provide this exibility providing dispatchable power as geothermal power plants are developed. With greater geothermal development, stakeholder management is critical, at public, regional and governmental levels. This is particularly true for the development of enhanced geothermal systems (EGS). Poor communication and education within local communities regarding the value of regional and local energy resources, potential hazards and their mitigation or management, could lead to backlash and even social rejection. If managed properly, the geothermal resource could provide signi cant decarbonization of the power needs for megacities. In addition, geothermal can bring local bene ts (e.g. job creation) and reduce the public expense in the energy sector. GEOENVI (2020) recently reported that geothermal has brought an annual saving of 2.6% of GDP to the Icelandic economy.
Geothermal power is both a baseload source and exible, thus providing the perfect partner with wind and solar-PV and hydroelectric resources. Given the geotectonic position of the world's megacities, we see a huge potential for the use of geothermal power which would also reduce the environmental impact and help contrasting the energy challenge in overpopulated areas. It should be noted that lower grade solutions utilizing direct use technologies such as Ground Source Heat Pumps (GSHP) and district energy systems, provide additional baseload decarbonization of heating and cooling needs. Such technologies, if retro tted into existing building stock and implemented in new buildings, reduce the primary electric demand (Ball et al. 2021a, b). Finally, if all geothermal solutions are investigated, including the direct use of geothermal district heating and GSHP's, then additional bene ts of a low-carbon energy system may be found, raising the quality of life for many people and helping to reduce energy poverty.

Conclusions
The use of geothermal energy near to megacities located along the margins of tectonic plates may guarantee a sustainable and resilient form of energy to supply decarbonizing residential, industry, transportation and other needs. Critical to the uptake of geothermal energy, however, is a positive government action that may include a carbon tax, investment into research and development of geothermal resources and the establishment of policies or tax-breaks that encourage the exploration and development of geothermal resources.  Figure 1 Worldwide distribution of geothermal gradient anomalies. Locations of volcanic belts and hydrocarbons occurrences have been combined with distribution of megacities. Note: The designations employed and the presentation of the material on this map do not imply the expression of any opinion whatsoever on the part of Research Square concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors.

Figure 2
Upper: Distribution of seismicity in NW Colombia. Green-dashed line highlights the presence of a 240-kmlong offset that displaces the subduction seismicity, which is called Caldas Tear. Lower: Geothermal gradient anomalies presented with spring-water occurrences (yellow circles), and O&G elds (purple diamonds). Black lines correspond to tectonic features. Red triangles are active volcanoes. Note: The designations employed and the presentation of the material on this map do not imply the expression of any opinion whatsoever on the part of Research Square concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors. territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors.   Upper-left map shows spring water occurrences (purple squares) near to Jakarta (Indonesia). Upper-right map presents estimations of the Curie Point Depth (CPD) on same region . Yellow-dashed ellipse represents a hypothetical envelope that encompasses the main geothermal leads. Maps present active volcanoes (red triangles), and O&G elds (yellow dots). Topography from Amante and Eakins (2009). Note: The designations employed and the presentation of the material on this map do not imply the expression of any opinion whatsoever on the part of Research Square concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors.

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