Nealtican lava flow field, Popocate'petl volcano: A window to the past
and future hazards

Date:
March 4, 2022
Source:
Geological Society of America
Summary:
The Popocate'petl volcano, located southeast of Mexico City, stands
as the second highest peak in Mexico and is considered to be one
of the potentially most dangerous volcanoes in the world, given
its record of highly explosive eruptions over the last 23,000 years.



FULL STORY ==========================================================================
The Popocate'petl volcano, located southeast of Mexico City, stands as
the second highest peak in Mexico and is considered to be one of the potentially most dangerous volcanoes in the world, given its record of
highly explosive eruptions over the last 23,000 years.


========================================================================== Scientists have been studying the record of past eruptions from
Popocate'petl to better understand possible future eruption scenarios
and to mitigate potential risks. A new study published 25 February in
GSA Bulletin took a focused look at one of the largest lava flows from Popocate'petl -- the Nealtican lava flow -- to evaluate its emplacement mechanisms and assess future volcanic hazards.

Researchers studied the lava flow in its entirety by mapping units of
the lava flow, analyzing its forms and features, and performing chemical
and mineral analyses of the rocks.

"All of this work helps us to reconstruct the eruptive history of
this flow and to determine exactly what the basic characteristics
were for this eruption to occur," said Israel Rami'rez-Uribe, the lead
author of this study. "It's important to study these phenomena so that
we can better anticipate future scenarios and mitigate the risks."
Co-author Dr. Claus Siebe said, "We can determine the areas that have
been affected by past eruptions and then speculate on areas that may
be affected in the future. And if these areas are inhabited by people,
we can tell whether they might suffer the consequences of an eruption in
the future." The Nealtican lava flow covers an area of ~70 km2 to the
east of Popocate'petl and was formed shortly after a highly explosive
eruption known as the Lorenzo Pumice, which is dated between 350-50
BCE. From examining the layers of volcanic material, the Nealtican lava
flow likely erupted only months to years after the explosive Lorenzo
Pumice eruption.



========================================================================== Unlike the oozing, low-viscosity lava flows we often see from volcanoes
in Hawaii, researchers determined that the Nealtican lava flows would
have had a much higher viscosity, traveling at a rate of only 1-33 meters
per day. Based on reconstructed eruption rates, it likely took ~35 years
for the whole Nealtican lava field to be emplaced.

While a lava flow moving this slowly would not pose a direct risk for
loss of human life, it would fully destroy existing structures and
permanently render agricultural areas useless.

The Nealtican lava flows and the preceding explosive Lorenzo Pumice
eruption would have significantly impacted pre-Hispanic settlements,
burying villages under volcanic material and causing an exodus of
the local population. Part of the pre-Hispanic Tetimpa settlement is
currently buried under ash and 30-100 m of lava, but the full impact of
the eruption on settlements closer to the volcano isn't known.

"The archeological site of Tetimpa seems to be the outskirts of
settlements that are buried under tens of meters of lava flows, so the
main archeological material is still lying under the lavas and won't be
easy to access." said Siebe.

Notably, the rise and fall of large Mesoamerican cities like Teotihuaca'n
and Cholula coincide with the last major explosive eruptions from Popocate'petl.

The population exodus and subsequent relocation as a result of the
volcanic eruptions may have led to the rise of these important cities
in central Mexico.

If Popocate'petl produced a lava flow today similar to the extent of
the Nealtican lava field, it could severely damage the infrastructure
of existing towns in the vicinity of the volcano and displace local
residents, as it has in the past.

The millions of residents in the vicinity of Popocate'petl should be
prepared and aware of these volcanic hazards, as it is not a question
of if the volcano will erupt, but when.

"This volcano is an active volcano, and we don't know when it will have
a high magnitude eruption again, but it will certainly have one, and we
should be ready for that," said Siebe.

Rami'rez-Uribe noted that "we must work with the communities at risk
and try to explain volcanic hazards and their effects not only from
a technical perspective, but also considering the socio-cultural
aspects, religious beliefs, and the worldview of inhabitants." ========================================================================== Story Source: Materials provided by Geological_Society_of_America. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Israel Rami'rez-Uribe, Claus Siebe, Magdalena Oryae"lle Chevrel,
Dolors
Ferres, Sergio Salinas. The late Holocene Nealtican lava-flow field,
Popocate'petl volcano, central Mexico: Emplacement dynamics and
future hazards. GSA Bulletin, 2022; DOI: 10.1130/B36173.1 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220304101011.htm

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