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Stephanie Grocke
Volcanologist
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Gabby Salazar
Photographer
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Ross Donihue
Cartographer
ThethreeexplorersmetbychanceatNationalGeographicheadquartersthreeyearsago.Theywereattendingameetingofscientistsandadventurers.Ittookonlyafewminutesforthemtorealizetheywouldmakeperfectpartners.StephanieGrockewasa volcanologist.GabbySalazarwasaphotographer.RossDonihuewasa cartographer.GrockewantedtotellthestoryofavolcanicsystemshehadbeenstudyinginGuatemala.Soon,SalazarandDonihuewerehookedontheidea, too.
AnExplosiveStart
In1902,theSantaMaríavolcanoinGuatemalahadamajoreruption.Theeventdestroyedthesurroundinglandscape.Itleftahugecraterinthemountainside.Italsoleftalotofashandrock.Later,lavaflowsbeganeruptingatthebasein1922.Overtime,thelavacreatedagroupof lavadomesnamed Santiaguito.
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Pumiceisalightweightvolcanic rock.
![](/nationalgeographic/trailblazer_november_december_2018/an_explosive_start_and_a_place_to_study/192244/plume.640_0_1.jpg)
Aplumeofashfroman eruptionrisesabovethe clouds.
Lavadomesformwhenstickymagmaeruptsfrom a vent.ItpoursontoEarth.OnEarth’ssurface,magmaiscalledlava.Thelavahereistoothicktoflowfar.So,itpilesup,makingalargedome.Calientewasthefirstdome. La Mitad,El Monje,andEl Brujo followed.
APlacetoStudy
Since1922,therehavebeenmanyeruptionsamongthefourlavadomes.Theyhappensooften,theyfeelnormaltothosewholive nearby.
ToGrocke,thisistheperfectplacetostudyactivevolcanoes.Shewantedtotestanewwaytocheckonlava‑dome activity.
Photogrammetryisatypeoftime‑lapsephotography.Itallowsyoutoobservechangesovertime.SheknewSalazarcouldhelpwith this.
Donihuewouldmaptheirexpedition.Hewouldalsomakeinfographicsaboutthelavadomesandtakepicturesfroma drone.
SantiaguitoComplex
The1902eruptionofSantaMaríaproducedahugecrater.Overtime,fourlavadomesformedatits base.
seismicmonitoring station
Santa María
El Caliente
La Mitad
El Monje
El Brujo
Observatory
GULFOF MEXICO
ATLANTIC
OCEAN
NORTH AMERICA
GUATEMALA
Santiaguito Complex
CARIBBEAN SEA
PACIFIC
OCEAN
SOUTH
AMERICA