Pacitalia
07-02-2007, 05:30
From Scientific Pacitalian print edition, Earth Sciences section, February 2007
http://kfox.gamehorizons.net/ScientificPacitalian.png
Shifting fortunes
Seismologists predict imminent doomsday but
can't tell us when "the big one" will happen
CABO SANTO LUCASI, MERITATE, PACITALIA
Last week's minor tremor in the Samarprian Gulf was a sobering reminder that the Transitional Republic lives on one of the world's most dangerous seismologically active zones. While no damage or death occurred, the forty seconds of shaking was enough for seismologists and geologists to jointly warn the Pacitalian public, but especially those living in geographically violent southwestern Meritate, of an imminent superquake whose seismic waves could literally disintegrate everything in their path, reducing the northwestern part of the country to rubble and ashy blackness.
Southwestern Meritate faces perhaps the biggest threat among the active seismic zones. The extremely irritable Sant'Andreosso fault is a spur off of the major Western Pacitalian fault line to the west of the Pacitalian mainland. The strike-slip Sant'Andreosso passes semi-perpendicular to the WPF and has two easting frays, off the coast of Puerta Vallarta, which add to the volatility and instability of the fault region. Passing through a deep, "v"-shaped channel of water, called the Samarprian Gulf, the Sant'Andreosso fault has presented the region with four of its five largest seismic disruptions on record, one of which occurred just last week, and which appears to be a precursor, a foreshadowing of an imminent earthquake that will, seismologists say, create catastrophic amounts of damage and human casuality. And while the Western Pacitalian Fault has long been proportionally more active than its smaller Meritatan counterpart, the 589.2km-long Sant'Andreosso had an average of 7.3 disruptions per hour between 1st January, 2006 and the same date one year later. This includes, as mentioned, a magnitude M3.70 earthquake, at midday on the 31st January, 2007, at the confluence of the spur fault and its most volatile fray line.
Geography
Southwestern Meritate is an active, supracatalytic seismic zone whose landscape was formed mostly by terranes and rough-aquatic terraforming nearly 110 million years ago. This date is an estimate, via biostratigraphic measurement. Both the Lucanian and Capassan islands are terranes from 35-50 million years ago, while much of the immediate western coast of the mainland is formed from terranes that have settled and are slightly more aged (in geological time), dated at about 80 million years old. The subductive process of the Carcossian Plate under the Foringanan Plate dragged terranes, that developed from accumulations of igneovolcanic rock from the Mid-Carcossian Ridge. The ridge, lying nearly exactly halfway between Hypocria and Falcania in the west, and Pacitalia in the east, in the Marazulan Sea, is a divergent plate margin between the Verdenan and Carcossian plates and allows the upwelling of magma into the seafloor, pushing the plates apart. This is where the terranes formed, then clasping precariously onto either plate to be dragged in opposite directions to the continents' boundaries and coastlines. These terranes, in Pacitalia, then accreted along less elevationally violent landscape, mostly arid steppe on a passive Ractor line, a geology term for a benign division between two, three or multiple formations of rock or crust.
These differences can be seen along a divisive line between the placement of the first accreted terranes and the steppe. Using a device called a cross-sectional seismogeological graphicator, University of Central Antigonia seismologist Prof Dr Gabriella Donnadona and University of Sambuca geologist Prof Dr Mariano Soria, determined, from west to east along a 7km cross-section, an abrupt end to formations of igneous rock on the western half of the sectional, and the immediate commencement of older layers of silt and claystone sedimentary rock(1), indicating the clear presence of those terranes. These formations have helped geologists like Dr Soria to understand what is happening to the landforms in northwestern Pacitalia over extended periods of time, but also to help their seismologist counterparts, like Dr Donnadona, to understand whether the region lies in danger of future natural calamities. But these terranes only dot the coastline, as, where they may have existed before, erosive rivers have excised wide, cone-shaped, flat and low-lying floodplains that contain extremely fertile soils and open up onto the seafronts. The most notable, and only large floodplain in the immediate region is nearly completely swallowed up by the resort of Puerta Vallarta, a sprawling, bustling madhouse of 620,000 residents, predominantly Spanish-descended, and nearly, every day, two million tourists, a number that grows larger during the cooler season.
Study of the terranes' path from the divergent margin in the Marazulan Sea to their current home dotting the region's coastline has led seismologists to another startling discovery: at first thought a coincidence, but on further study, no less than simple science. The rough rock of the terranes abraded the surface of the ocean floor as it graded east to the continental boundary, and like glass into the skin, cut a deep wound into the crust that only excavated further into the Earth's topmost layer through usual plate tectonic movement. These terranes are directly responsible not for the creation of the Western Pacitalian Fault, but for weakening the crust to engineer spur faults and fray lines that have markedly increased the potential instability of the terraforms of southwestern Meritate.
Geological signs
In presenting their warnings and assertions, the seismologists, from the University of Central Antigonia's Faculty of Geography, which issued the report, say there have been multiple signs pointing to the imminent slippage of the spur fault(2). And they say that as more and more of these little alarm clocks go off Meritatans crawl ever closer to their impending nightmare.
The first major sign has been fault, plate and GPS tracking device movement. Drs Donnadona and Soria conducted another experiment to complement their cross-sectional terraform research, starting in 2000 and ending in 2006, in which they placed GPS tracking devices at six points around the Samarprian Gulf, two on Isola Lucania, two in the gulf waters on buoys, and two on the mainland coastline(3). At the start of the research, the six tracking devices formed a mathematically perfect circle, accurate to 20 million decimal places, around the confluence of the Sant'Andreosso and its southern fray line, a fault-line intersection they were greatly concerned over in terms of possible future slippage. By the time they finished collecting data on the last day of 2006, the tracking devices on Isola Lucania had shifted 39.7mm east of their original location, hinting that the island, the largest terrane yet to form from the Mid-Carcossian Ridge divergence, was moving toward the mainland at an average of 6.62mm per year. In human terms that is irrelevant or unimportant, but in geological terms such movement is massive and unthinkable. The movement equates to an increase in the tension along the Sant'Andreosso of around 7 percent year-to-year, meaning that the fault would reach its full tensile capacity by 2014. That, of course, as the seismologists, and Drs Donnadona and Soria say, is inaccurate, because for the doomsday date to be correct, tension on the fault would have had to be absolutely zero at the start of the experiment, which it was not and never had been(4). There is no way to correctly, let alone accurately, measure tension on a fault, which means there is no way to predict when earthquakes will occur. But we do know that the fault's tensile capacity is decreasing because of an increase in actual tension along the strike-slip.
Second among the indications that a major earthquake is imminent is the increased activity of the region's active volcanoes. Volcanoes are a trademark of any subduction zone, and this region in particular has six: Mamanoni and Lidaceno on Isola Capasso, and Arbazona, Saronica, Melevanto and Ciapace on the mainland. The activity has been limited to the emission of volcanic gases, and so far the two volcanoes on Isola Capasso have remained in their short-term dormancy. But the four active volcanoes are of great concern to seismologists, because a powerful enough eruption could create sufficient shaking to relieve the tension on the Sant'Andreosso spur fault, or farther away, relieve the tension on the subduction zone, creating a longer-lasting, but possibly not as intense, seismic disruption.
The third indication of an imminent earthquake is the developing tensional cracks at the confluences of the three plates, both north and south. The Lucanian Plate is what geologists call a continental-passive plate (CtPa), so it behaves like an island in a proverbial tectonic sea, sitting stationary between its larger cousins, the Carcossian and Foringanan plates. The Carcossian plate is an oceanic plate, so it subducts under its abductive, continental Foringanan counterpart. These three plates meet in two places, north and south, and where this occurs marks the delineated difference between the behaviour of the Carcossian Plate against its neighbour. As the Lucanian Plate is passive, it is merely bumping up against the Carcossian Plate in what geologists call a convergent plate boundary. But when the Lucanian Plate ends the areas of subduction underneath the Foringanan Plate commence, creating an unusual geological traffic jam, where parts of the oceanic plate are still successfully pushing their way under the continent, but where other sections are left bumping up against the passive, "third party" plate. So where these changes in plate behaviour occur, new spur faults are developing, burrowing west into the Carcossian Plate. The new southern spur fault is growing west at a rate of 1km per year (it is already nearly 170km long).
Geologists are concerned about this area because, among the five largest earthquakes recorded in this region, the most powerful of them (an M7.0 quake) happened at the exact point of contention for the doomsday scenario. Geologists are also concerned about these new faults based on what they already know about volatile spurs, but also because they know comparatively little about what they have now christened back-channeling spurs (spur faults that recede retroactively into the subducting plate). The general consensus(5) is that once these faults develop they will actually relieve the tension caused by the acute difference in plate behaviour in a shocking new way - abruptly, within mere seconds, snapping the oceanic plate into three smaller pieces, which would create a seismic disruption so large it would register above the current means of the Richter scale. This would be an earthquake so powerful that it would fold the Lucanian Plate under its two neighbours and return the coastline to a natural, uniform subduction instead of having the obstacle of a small, passive plate. Because of the violent nature of the sudden snapping of the Carcossian Plate, the subcrustal folding would only take about seven to ten minutes, leaving those trapped on Isola Lucania with no time to escape, and resulting in the deaths of millions.
Social implications
So, now that the warning has been issued, how prepared are Pacitalian authorities in dealing with the apparently inevitable disaster? The answer: surprisingly, quite well. Pacitalian authorities provide documentation, emergency preparedness kits and frequent education seminars and do not play the dangerous game of chicken, or of ignorance, with geography. All three levels of government are fully aware of the damage a major earthquake can do, and civilian and emergency services training has been stepped up dramatically ever since the 7.2 earthquake which happened in November 2004 and which was centred west of Timiocato along the Western Pacitalian fault. Tourists and visitors are invited to share in the training just in case the big one does hit while they are in Pacitalia, and this invitation is extended on a well-constructed pamphlet given to entrants at the customs booths in their ports of entry. This information is especially useful for those visitors coming from countries that do not hold worry or anxiety over seismic activity.
While Pacitalian health care is privatised it is still free for visitors who require medical attention and can produce the correct documentation, such as health care provision cards or insurance forms. Evacuation routes are clearly delineated and there have already been a set of rules and regulations established, and protocols to follow, in the event of a natural disaster. There are contigency plans for food, shelter and clothing provision, healthcare provision and for alternative sources of clean water, and the management of law enforcement provisions. They have planned to provide only the necessities until authorities and the workforce can rebuild the region back to its normal, original state.
Economic implications
No doubt with the scale of disaster predicted by these seismologists there will be massive economic implications. The policy on dealing with the economy can never be finalised because, in a natural disaster of such scope, decisions always have to be made as the need arises and as the situation permits. There are no plans that can be made that will suitably and effectively deal with the natural disaster, except through sheer luck. What can be done, however, is to form a general plan of attack, in order to organise the rebuilding and reconstitution of the region in an orderly and proper fashion, first returning essential infrastructure to normal, then focusing on assisting the private sector in restoring services and industry. Since 1995, Timiocato has been cooperating with Bergamo (the provincial capital of Meritate) and various municipal authorities in the southwestern part of the province, to develop basic contingency plans for economic recovery. So while the governments and authorities are prepared to handle, it is just a matter of keeping the public (and the marketplace) calm in the face of impending disaster.
In summation
There is nothing humans can do to reverse the possible damage of a natural disaster: the Earth is the one thing we cannot change instantly. While consensus is that we have caused global warming, this is an unrelated problem, a natural process of the Earth to which humans must simply learn to adjust. The region's beauty may be forever altered but as long as its inhabitants and visitors are prepared for the worst, it will most probably go rather smoothly. The possibility of the doomsday scenario where the Lucanian Plate disappears into the Earth all together is still a relative longshot, and seismologists are more concerned about a major earthquake occurring in general. It all comes down to a nervewracking, anxious waiting game, where we remain, desperately watching the proverbial alarm clock even though there is no fixed countdown.
______________________
(1) Donadonna, Prof Dr Gabriella, and Prof Dr Mariano Soria. A Geographic and Geologic Exploration of Northern Pacitalia. Timiocato: Conapresso Sienciata Unicà SpA, 2001, pp86-96.
(2) Faculty of Geography, University of Central Antigonia. Positional Paper of Consensus, 2006: Volcanism and Tectonics in Meritate. Nortopalazzo: Conapresso UCA SpA, 2006.
(3) Ibid.
(4) Ibid. Corroborated by Donadonna et al., (1).
(5) Ibid.
______________________
SP:Interactive
Check out http://features.scientific.pc/E337706 (http://kfox.gamehorizons.net/meritategeology.png) for a detailed seismotopographic map of the region discussed in this Earth Sciences lead feature.
http://kfox.gamehorizons.net/ScientificPacitalian.png
Shifting fortunes
Seismologists predict imminent doomsday but
can't tell us when "the big one" will happen
CABO SANTO LUCASI, MERITATE, PACITALIA
Last week's minor tremor in the Samarprian Gulf was a sobering reminder that the Transitional Republic lives on one of the world's most dangerous seismologically active zones. While no damage or death occurred, the forty seconds of shaking was enough for seismologists and geologists to jointly warn the Pacitalian public, but especially those living in geographically violent southwestern Meritate, of an imminent superquake whose seismic waves could literally disintegrate everything in their path, reducing the northwestern part of the country to rubble and ashy blackness.
Southwestern Meritate faces perhaps the biggest threat among the active seismic zones. The extremely irritable Sant'Andreosso fault is a spur off of the major Western Pacitalian fault line to the west of the Pacitalian mainland. The strike-slip Sant'Andreosso passes semi-perpendicular to the WPF and has two easting frays, off the coast of Puerta Vallarta, which add to the volatility and instability of the fault region. Passing through a deep, "v"-shaped channel of water, called the Samarprian Gulf, the Sant'Andreosso fault has presented the region with four of its five largest seismic disruptions on record, one of which occurred just last week, and which appears to be a precursor, a foreshadowing of an imminent earthquake that will, seismologists say, create catastrophic amounts of damage and human casuality. And while the Western Pacitalian Fault has long been proportionally more active than its smaller Meritatan counterpart, the 589.2km-long Sant'Andreosso had an average of 7.3 disruptions per hour between 1st January, 2006 and the same date one year later. This includes, as mentioned, a magnitude M3.70 earthquake, at midday on the 31st January, 2007, at the confluence of the spur fault and its most volatile fray line.
Geography
Southwestern Meritate is an active, supracatalytic seismic zone whose landscape was formed mostly by terranes and rough-aquatic terraforming nearly 110 million years ago. This date is an estimate, via biostratigraphic measurement. Both the Lucanian and Capassan islands are terranes from 35-50 million years ago, while much of the immediate western coast of the mainland is formed from terranes that have settled and are slightly more aged (in geological time), dated at about 80 million years old. The subductive process of the Carcossian Plate under the Foringanan Plate dragged terranes, that developed from accumulations of igneovolcanic rock from the Mid-Carcossian Ridge. The ridge, lying nearly exactly halfway between Hypocria and Falcania in the west, and Pacitalia in the east, in the Marazulan Sea, is a divergent plate margin between the Verdenan and Carcossian plates and allows the upwelling of magma into the seafloor, pushing the plates apart. This is where the terranes formed, then clasping precariously onto either plate to be dragged in opposite directions to the continents' boundaries and coastlines. These terranes, in Pacitalia, then accreted along less elevationally violent landscape, mostly arid steppe on a passive Ractor line, a geology term for a benign division between two, three or multiple formations of rock or crust.
These differences can be seen along a divisive line between the placement of the first accreted terranes and the steppe. Using a device called a cross-sectional seismogeological graphicator, University of Central Antigonia seismologist Prof Dr Gabriella Donnadona and University of Sambuca geologist Prof Dr Mariano Soria, determined, from west to east along a 7km cross-section, an abrupt end to formations of igneous rock on the western half of the sectional, and the immediate commencement of older layers of silt and claystone sedimentary rock(1), indicating the clear presence of those terranes. These formations have helped geologists like Dr Soria to understand what is happening to the landforms in northwestern Pacitalia over extended periods of time, but also to help their seismologist counterparts, like Dr Donnadona, to understand whether the region lies in danger of future natural calamities. But these terranes only dot the coastline, as, where they may have existed before, erosive rivers have excised wide, cone-shaped, flat and low-lying floodplains that contain extremely fertile soils and open up onto the seafronts. The most notable, and only large floodplain in the immediate region is nearly completely swallowed up by the resort of Puerta Vallarta, a sprawling, bustling madhouse of 620,000 residents, predominantly Spanish-descended, and nearly, every day, two million tourists, a number that grows larger during the cooler season.
Study of the terranes' path from the divergent margin in the Marazulan Sea to their current home dotting the region's coastline has led seismologists to another startling discovery: at first thought a coincidence, but on further study, no less than simple science. The rough rock of the terranes abraded the surface of the ocean floor as it graded east to the continental boundary, and like glass into the skin, cut a deep wound into the crust that only excavated further into the Earth's topmost layer through usual plate tectonic movement. These terranes are directly responsible not for the creation of the Western Pacitalian Fault, but for weakening the crust to engineer spur faults and fray lines that have markedly increased the potential instability of the terraforms of southwestern Meritate.
Geological signs
In presenting their warnings and assertions, the seismologists, from the University of Central Antigonia's Faculty of Geography, which issued the report, say there have been multiple signs pointing to the imminent slippage of the spur fault(2). And they say that as more and more of these little alarm clocks go off Meritatans crawl ever closer to their impending nightmare.
The first major sign has been fault, plate and GPS tracking device movement. Drs Donnadona and Soria conducted another experiment to complement their cross-sectional terraform research, starting in 2000 and ending in 2006, in which they placed GPS tracking devices at six points around the Samarprian Gulf, two on Isola Lucania, two in the gulf waters on buoys, and two on the mainland coastline(3). At the start of the research, the six tracking devices formed a mathematically perfect circle, accurate to 20 million decimal places, around the confluence of the Sant'Andreosso and its southern fray line, a fault-line intersection they were greatly concerned over in terms of possible future slippage. By the time they finished collecting data on the last day of 2006, the tracking devices on Isola Lucania had shifted 39.7mm east of their original location, hinting that the island, the largest terrane yet to form from the Mid-Carcossian Ridge divergence, was moving toward the mainland at an average of 6.62mm per year. In human terms that is irrelevant or unimportant, but in geological terms such movement is massive and unthinkable. The movement equates to an increase in the tension along the Sant'Andreosso of around 7 percent year-to-year, meaning that the fault would reach its full tensile capacity by 2014. That, of course, as the seismologists, and Drs Donnadona and Soria say, is inaccurate, because for the doomsday date to be correct, tension on the fault would have had to be absolutely zero at the start of the experiment, which it was not and never had been(4). There is no way to correctly, let alone accurately, measure tension on a fault, which means there is no way to predict when earthquakes will occur. But we do know that the fault's tensile capacity is decreasing because of an increase in actual tension along the strike-slip.
Second among the indications that a major earthquake is imminent is the increased activity of the region's active volcanoes. Volcanoes are a trademark of any subduction zone, and this region in particular has six: Mamanoni and Lidaceno on Isola Capasso, and Arbazona, Saronica, Melevanto and Ciapace on the mainland. The activity has been limited to the emission of volcanic gases, and so far the two volcanoes on Isola Capasso have remained in their short-term dormancy. But the four active volcanoes are of great concern to seismologists, because a powerful enough eruption could create sufficient shaking to relieve the tension on the Sant'Andreosso spur fault, or farther away, relieve the tension on the subduction zone, creating a longer-lasting, but possibly not as intense, seismic disruption.
The third indication of an imminent earthquake is the developing tensional cracks at the confluences of the three plates, both north and south. The Lucanian Plate is what geologists call a continental-passive plate (CtPa), so it behaves like an island in a proverbial tectonic sea, sitting stationary between its larger cousins, the Carcossian and Foringanan plates. The Carcossian plate is an oceanic plate, so it subducts under its abductive, continental Foringanan counterpart. These three plates meet in two places, north and south, and where this occurs marks the delineated difference between the behaviour of the Carcossian Plate against its neighbour. As the Lucanian Plate is passive, it is merely bumping up against the Carcossian Plate in what geologists call a convergent plate boundary. But when the Lucanian Plate ends the areas of subduction underneath the Foringanan Plate commence, creating an unusual geological traffic jam, where parts of the oceanic plate are still successfully pushing their way under the continent, but where other sections are left bumping up against the passive, "third party" plate. So where these changes in plate behaviour occur, new spur faults are developing, burrowing west into the Carcossian Plate. The new southern spur fault is growing west at a rate of 1km per year (it is already nearly 170km long).
Geologists are concerned about this area because, among the five largest earthquakes recorded in this region, the most powerful of them (an M7.0 quake) happened at the exact point of contention for the doomsday scenario. Geologists are also concerned about these new faults based on what they already know about volatile spurs, but also because they know comparatively little about what they have now christened back-channeling spurs (spur faults that recede retroactively into the subducting plate). The general consensus(5) is that once these faults develop they will actually relieve the tension caused by the acute difference in plate behaviour in a shocking new way - abruptly, within mere seconds, snapping the oceanic plate into three smaller pieces, which would create a seismic disruption so large it would register above the current means of the Richter scale. This would be an earthquake so powerful that it would fold the Lucanian Plate under its two neighbours and return the coastline to a natural, uniform subduction instead of having the obstacle of a small, passive plate. Because of the violent nature of the sudden snapping of the Carcossian Plate, the subcrustal folding would only take about seven to ten minutes, leaving those trapped on Isola Lucania with no time to escape, and resulting in the deaths of millions.
Social implications
So, now that the warning has been issued, how prepared are Pacitalian authorities in dealing with the apparently inevitable disaster? The answer: surprisingly, quite well. Pacitalian authorities provide documentation, emergency preparedness kits and frequent education seminars and do not play the dangerous game of chicken, or of ignorance, with geography. All three levels of government are fully aware of the damage a major earthquake can do, and civilian and emergency services training has been stepped up dramatically ever since the 7.2 earthquake which happened in November 2004 and which was centred west of Timiocato along the Western Pacitalian fault. Tourists and visitors are invited to share in the training just in case the big one does hit while they are in Pacitalia, and this invitation is extended on a well-constructed pamphlet given to entrants at the customs booths in their ports of entry. This information is especially useful for those visitors coming from countries that do not hold worry or anxiety over seismic activity.
While Pacitalian health care is privatised it is still free for visitors who require medical attention and can produce the correct documentation, such as health care provision cards or insurance forms. Evacuation routes are clearly delineated and there have already been a set of rules and regulations established, and protocols to follow, in the event of a natural disaster. There are contigency plans for food, shelter and clothing provision, healthcare provision and for alternative sources of clean water, and the management of law enforcement provisions. They have planned to provide only the necessities until authorities and the workforce can rebuild the region back to its normal, original state.
Economic implications
No doubt with the scale of disaster predicted by these seismologists there will be massive economic implications. The policy on dealing with the economy can never be finalised because, in a natural disaster of such scope, decisions always have to be made as the need arises and as the situation permits. There are no plans that can be made that will suitably and effectively deal with the natural disaster, except through sheer luck. What can be done, however, is to form a general plan of attack, in order to organise the rebuilding and reconstitution of the region in an orderly and proper fashion, first returning essential infrastructure to normal, then focusing on assisting the private sector in restoring services and industry. Since 1995, Timiocato has been cooperating with Bergamo (the provincial capital of Meritate) and various municipal authorities in the southwestern part of the province, to develop basic contingency plans for economic recovery. So while the governments and authorities are prepared to handle, it is just a matter of keeping the public (and the marketplace) calm in the face of impending disaster.
In summation
There is nothing humans can do to reverse the possible damage of a natural disaster: the Earth is the one thing we cannot change instantly. While consensus is that we have caused global warming, this is an unrelated problem, a natural process of the Earth to which humans must simply learn to adjust. The region's beauty may be forever altered but as long as its inhabitants and visitors are prepared for the worst, it will most probably go rather smoothly. The possibility of the doomsday scenario where the Lucanian Plate disappears into the Earth all together is still a relative longshot, and seismologists are more concerned about a major earthquake occurring in general. It all comes down to a nervewracking, anxious waiting game, where we remain, desperately watching the proverbial alarm clock even though there is no fixed countdown.
______________________
(1) Donadonna, Prof Dr Gabriella, and Prof Dr Mariano Soria. A Geographic and Geologic Exploration of Northern Pacitalia. Timiocato: Conapresso Sienciata Unicà SpA, 2001, pp86-96.
(2) Faculty of Geography, University of Central Antigonia. Positional Paper of Consensus, 2006: Volcanism and Tectonics in Meritate. Nortopalazzo: Conapresso UCA SpA, 2006.
(3) Ibid.
(4) Ibid. Corroborated by Donadonna et al., (1).
(5) Ibid.
______________________
SP:Interactive
Check out http://features.scientific.pc/E337706 (http://kfox.gamehorizons.net/meritategeology.png) for a detailed seismotopographic map of the region discussed in this Earth Sciences lead feature.