Lesson on TATAKalikasan, Ateneo de Manila University
87.9 FM Radyo Katipunan, every Thursday, 11 - 12 a.m. Nov 6, 2025
Volcanoes and Calderas
Host, Fr JM Manzano SJ, with Dr Abe V Rotor, Prof Emoy Rodolfo, AdMU, and Prof. Pauline Salvana Bautista, Ateneo School of Theology
Guest: Prof. Jenny Anne Barretto, discoverer of Apolaki Caldera
The Apolaki Caldera was discovered in 2019 by Jenny Anne Barretto, a Filipino marine geophysicist, and her team. This caldera is recognized as the world's largest, located within the Benham Rise.
The World’s Largest Caldera
Discovered in the Philippine Sea
By David Bressan, Senior Contributor. Oct 21, 2019.
A 150 km wide depression discovered during a survey in the Philippine Sea may be the world's largest volcanic caldera.Google Earth/Barretto et al. 2019
A team of marine geophysicists recently published a paper describing a large igneous massif east of the island of Luzon, located on the bottom of the Philippine Sea. Based on the morphology, the research suggests that the submarine mountain massif represents the remains of a volcanic caldera with a diameter of ~150 km (93 miles), twice the size of the famous Yellowstone caldera in Wyoming (U.S.).
The Benham Rise is rising from the 5.200 meters (~17,000 ft) deep seafloor to ~2500 meters, roughly 8,200 ft, beneath the sea surface, with a depression in the central portion, which likely is a volcanic caldera. When large volumes of magma are erupted over a short time, a volcano may collapses downward into the emptied or partially emptied magma chamber, leaving a massive depression at the surface, from one to dozens of kilometers in diameter. The circular depression on the Benham Rise is surrounded by a crest with scarps as high as 100 to 300 meters (300 to 900 ft). It may be the world's largest known caldera with a diameter of ~150 km (93 miles). For comparison, the famous caldera of Yellowstone in Wyoming is only about 60 km (37 miles) wide. The researchers named the caldera Apolaki, meaning “giant lord”, after the Filipino god of the sun and war.
Salient Informaion
- Taal Lake is part of a caldera. It fills the Taal Volcano, which is a large volcanic caldera formed by significant eruptions in prehistoric times. The lake occupies a bowl-shaped basin that opened when the top of the Taal volcano blew off during one of these eruptions. Thus, while Taal Lake itself is not a caldera, it is located within the caldera of the Taal Volcano.
The Yellowstone Caldera, a supervolcano located in Yellowstone National Park, has a history of significant eruptions, but current monitoring indicates that an eruption is not imminent.
The Yellowstone Caldera was formed by a series of massive volcanic eruptions, with the most recent occurring approximately 640,000 years ago. This eruption created the current caldera, which measures about 30 by 45 miles. The caldera has experienced three major eruptions in its history, with the first occurring around 2.1 million years ago.
Recent geological activity in the Yellowstone region has been closely monitored by the Yellowstone Volcano Observatory. As of late 2025, the caldera's activity remains at background levels, with minor seismic events reported, including 87 earthquakes in September 2025, the largest being a magnitude 3.3. The U.S. Geological Survey (USGS) has indicated that there is no immediate threat of a major eruption, and the volcanic system is not currently capable of producing such an event. The Yellowstone Caldera is characterized by its geothermal features, including hot springs, geysers, and fumaroles, which are evidence of the heat still present beneath the surface. The magma reservoirs beneath Yellowstone are complex, with large volumes of partially molten rock located 2.5 to 30 miles below the surface. While the caldera is active, the likelihood of a catastrophic eruption in the near future is considered low, and ongoing monitoring continues to assess any changes in volcanic activity.
Conclusion
In summary, while the Yellowstone Caldera is a significant geological feature with a history of explosive eruptions, current scientific assessments indicate that there is no immediate risk of a major eruption. The Yellowstone Volcano Observatory continues to monitor the area closely, ensuring that any changes in volcanic activity are detected and assessed promptly.
Here are some famous calderas in the world:
1. Yellowstone Caldera (USA): One of the most well-known calderas, located in Yellowstone National Park, it is a supervolcano with a massive eruption history.
2. Island Park Caldera (USA): Located in Idaho and Wyoming, it is one of the largest calderas, measuring approximately 80 by 65 km.
3. Long Valley Caldera (USA): Situated in California, this caldera formed from a massive volcanic eruption about 760,000 years ago.
4. Toba Caldera (Indonesia): Known for the supereruption that occurred around 74,000 years ago, it is one of the largest volcanic lakes in the world.
5. Aso Caldera (Japan): This caldera is one of the largest in the world and contains several active volcanoes within its boundaries.
ANNEX - 1
Mt Makiling - Endangered Geo-Ecosystem
"Everybody loves this legendary mountain, her majestic pose be near or far, reclining in peace and beauty." avr
Living with Nature School on Blog [avrotor.blogspot.com]
The mountain's profile of a reclining deity, Maria Makiling, to whom the mountain was named, has lost much of her youthful features.
Satellite image of Mt Makiling and southeastern shore of Laguna Bay. Mt Makiling has lost much of its original vegetative cover to encroaching human settlements, swiden (kaingin) farming, commerce and tourism. In fact the mountain's profile of a reclining deity, Maria Makiling for which the mountain is named, has lost much of her youthful
features.
Statue of Maria Makiling protector of Mt Makiling, UPLB Laguna.
On the trail to the Mudspring with the author's family. 
Mudspring Crater, author with his children.
A Trek to Mt Makiling's Mystical Crater - Mudspring
It's a long trail if you start at the foot of Mt Makiling,take the road with a four-wheel drive,then stop where the road ends and from here startsa long trek you really have to strive.
Among the huge towering trees you're but a dwarfamong creatures crawling or flying,searching far beyond of what they are looking for;theirs for living, yours for meaning.
Incessantly the crater pops scalding mudand gases that boggle the mind,a mystic shroud where mist and cloud meet,a spectacle of a different kind.
Everybody loves this legendary mountain,though fiery inside to be free;Lofty is her majestic pose be near or farreclining in peace and beauty.
Wonder the young mind thinks of this world,a hybrid of fantasy and reality,where spirits live and mortals dare to tread,in a lifetime's journey to infinity. ~
NOTE: Mount Makiling, or Mount Maquiling, is a dormant volcano in Laguna province on the island of Luzon, Philippines. The mountain rises to an elevation of 1,090 m (3,580 ft) above mean sea level and is the highest feature of the Laguna Volcanic Field. The volcano has no recorded historic eruption but volcanism is still evident through geothermal features like mud spring and hot springs. South of the mountain is the Makiling-Banahaw Geothermal Plant. The Philippine Institute of Volcanology and Seismology (PHIVOLCS) classify the volcano as potentially active.
Mount Makiling is a state-owned forest reserve administered by the University of the Philippines, Los Baños. Prior its transfer to the university, the mountain was the first national park of the Philippines. Mount Makiling National Park was established on February 23, 1933 by Proc. No. 552. However, it was decommissioned as a national park on June 20, 1963 by Republic Act no. 3523 when it was transferred to the University for use in forestry education and information.
Now known as Mount Makiling Forest Reserve, it was declared an ASEAN Heritage Park in 2013. (Wikipedia)
"Nature's peace will flow into you as sunshine flows into trees. The winds will blow their own freshness into you, and the storms their energy, while cares will drop off like autumn leaves."- —John Muir, Our National Parks
"This grand show is eternal. It is always sunrise somewhere; the dew is never all dried at once; a shower is forever falling; vapor is ever rising. Eternal sunrise, eternal sunset, eternal dawn and gloaming, on sea and continents and islands, each in its turn, as the round earth rolls."—John Muir, John of the Mountains: The Unpublished Journals of John Muir
"There is a pleasure in the pathless woods,
There is a rapture on the lonely shore,There is society, where none intrudes,By the deep Sea, and music in its roar:I love not Man the less, but Nature more."—Lord Byron "Childe Harold's Pilgrimage"
"Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts. ... There is something infinitely healing in the repeated refrains of nature — the assurance that dawn comes after night, and spring after winter."—Rachel Carson, Silent Spring
"If we surrendered
to earth's intelligence
we could rise up rooted, like trees."
we could rise up rooted, like trees."
—Rainer Maria Rilke, Rilke's Book of Hours: Love Poems to God.~
ANNEX 2
Mayon Volcano - Gentle but Fiery
Mayon is a paradox. Tourists flock while residents escape danger; lava destroys but fertilizes the field, so with volcanic ash; it is self-destruct and self-healing. People curse, people revere.
Dr Abe V Rotor
This is how close I got over the crater of Mayon Volcano on Cebu Pacific flight from Manila to Iloilo in 2012. It was a bright morning with a dash of rainbow dramatically unveiling the majestic cone.
Old photos (August 14, 1928) showing the ruins of the church and belfry of Cagsawa after the 1814 eruption. (Acknowledgement: Internet)
Mayon is a paradox. Tourists flock while residents escape danger; lava destroys but fertilizes the field, so with volcanic ash; it is self-destruct and self-healing. People curse, people revere. Beauty begets beauty only after an episode of disaster. Science versus superstition; technology versus unpredictability; impermanence versus balance. Enigma is the word. (Acknowledgement: Internet, Wikipedia, National Geographic)
And what is peace and harmony? Perfection and symmetry? Gentleness and majesty? Ask the artist, the native of the place, the tourist, a survivor of eruptions, big and small. Ask a child, a balikbayan. (Acknowledgement: Internet, Wikipedia)
Left: This is how fire and water meet on the slope, cascading through gullies and solidifying in the process to become part of the volcano's perfect cone. Left: Before the catastrophic episode, the volcano groans as magma in its vowels expands and rises until the volcano can no longer contain the tremendous pressure. Result: eruption, a cyclic phenomenon that draws awe and fear, mystery and respect to this beautiful, enigmatic creation. (Paintings in acrylic by the author)
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