How the Philippine Island Arc was Formed | Dr. Carla Dimalanta

Summary

The video script delves into the geological makeup of the Philippines, an island arc system formed by tectonic plate interactions. It highlights the country's vulnerability to earthquakes due to its location at the junction of the Eurasian and Philippine Sea plates, and the monitoring of active volcanoes by the Philippine Institute of Volcanology and Seismology. The script also explores the geological history, including the formation of the Philippine mobile belt and the collision with the Palawan micro continental block, providing insights into the region's seismic activity and natural hazards.

Takeaways

• 🌍 The Philippines is an island arc system located southeast of Asia, formed by the collision and subduction of tectonic plates.
• 🗻 The country is composed of over 7,500 islands, with the Philippine Institute of Volcanology and Seismology monitoring 23 active volcanoes.
• 🔍 The geologic configuration of the Philippines makes it prone to earthquakes, with an average of 20 daily, though most are not felt.
• 📊 The most significant earthquake generators in the Philippines include the West Valley Fault and the Philippine Fault.
• 🏞️ The Palawan Block, which includes Palawan and nearby islands, is considered a micro continental block that was once part of mainland Asia.
• 🔬 New geological data and methodologies have provided insights into the ages and origins of rocks in the Philippine islands.
• 📝 Fossil evidence from the rocks in the Palawan Peninsula indicates that these rocks are around 156 million years old, suggesting a Jurassic age.
• 🗺️ Mindoro Island is also part of the Palawan micro continental block, with rocks dating back to 28 to 41 million years old.
• 🌋 The Long Island Group, including Lubang and Mindoro, contains metamorphic rocks with quartz grains, indicating a continental origin.
• 🔍 The study of rock samples from various parts of the Philippines has helped to piece together the geological history and the formation of the island arc system.

Q & A

What is the Philippines' geographical location?

The Philippines is an island arc system located southeast of the Asian landmass, between the Eurasian Plate and the Philippine Sea Plate.

What types of rocks are predominant in the Philippine islands?

The Philippine islands are primarily composed of volcanic, sedimentary, and metamorphic rocks.

How many active volcanoes does the Philippine Institute of Volcanology and Seismology monitor?

The Philippine Institute of Volcanology and Seismology monitors 23 active volcanoes throughout the country.

What are the most active volcanoes in the Philippines mentioned in the script?

The most active volcanoes mentioned are Mayon, Taal, and Pinatubo.

Why does the Philippines experience a high number of earthquakes?

The Philippines experiences many earthquakes due to its position at the margins of tectonic plates, where subduction and collision of geologic blocks result in seismic activity.

What is the average number of earthquakes the Philippines experiences daily?

On average, the Philippines experiences around 20 earthquakes daily.

What significant earthquake devastated Manila in 1968?

The significant earthquake that devastated Manila in 1968 had a magnitude of 7.3, with its epicenter located in Casiguran.

What is the role of the Palau microcontinental block in the formation of the Philippine island arc system?

The Palau microcontinental block, which originated from mainland Asia, collided with the Philippine mobile belt, contributing to the formation of the Philippine island arc system.

How did the study of rock samples from the Long Island group contribute to understanding the Philippine island arc system?

The study of metamorphic rocks from the Long Island group, characterized by the presence of quartz minerals, suggested that these islands were once part of the southern margin of mainland Asia, providing insights into the formation of the Philippine island arc system.

What evidence from the fossil record supports the connection between the Palawan microcontinental block and the Philippine island arc system?

Fossils extracted from the rocks in the Palawan Peninsula, such as nannofossils indicating a Jurassic age, support the connection between the Palawan microcontinental block and the formation of the Philippine island arc system.

What is the significance of the Mindoro Island in the context of the Philippine island arc system?

Mindoro Island, with its sedimentary rocks dating back to around 28 to 41 million years, is considered part of the Palawan microcontinental block, which is significant for understanding the broader geologic history of the Philippine island arc system.

What methodologies were used in the study of the Philippine island arc system?

Various methodologies were used, including geologic mapping, geophysical surveys, rock sample collection and analysis, and fossil examination to study the formation and evolution of the Philippine island arc system.

How does understanding the geologic history of the Philippines inform us about potential hazards in the country?

Understanding the geologic history and the processes that contributed to the formation of the Philippines can provide insights into the nature of geological hazards, such as earthquakes and volcanic activities, in the country.

Outlines

00:00

🌋 Geological Formation of the Philippine Islands

The Philippine archipelago is an island arc system located southeast of Asia, formed by the interaction of tectonic plates. It consists of over 7,500 islands with a complex geological history involving the subduction of materials along trenches, leading to earthquakes and volcanic activity. The Philippine Institute of Volcanology and Seismology monitors 23 active volcanoes, with notable ones being Mayon, Taal, and Pinatubo. The country experiences an average of 20 earthquakes daily, many of which are minor and go unnoticed. Historically, the Philippines has been hit by several destructive earthquakes, including the 1968 Casiguran earthquake and the 1990 Luzon earthquake. The script also mentions the absence of earthquakes in the Sulu Archipelago, which is part of the Palawan Block, a continental fragment that collided with the Philippine Mobile Belt.

05:01

🗺 Evolution of the Philippine Island Arc System

The evolution of the Philippine island arc system began with the separation of a fragment from mainland Asia, leading to the formation of the South China Sea. This fragment, known as the Palawan micro continental block, moved southeastward and collided with the northward-moving Philippine mobile belt. Technological advancements have allowed for more precise dating and analysis of rock samples, which are crucial for understanding the system's evolution. Geologists have focused on the central Philippines, particularly the Long Island group, to collect data on metamorphic rocks that suggest a connection to mainland Asia. Field mapping, laboratory analysis, and fossil evidence support the hypothesis that the Long Island group was once part of the southern margin of mainland Asia.

10:01

🔍 Investigating the Origins of Philippine Islands

The investigation into the origins of the Philippine islands involved geological mapping, geophysical surveys, and rock sample collection from various locations, including the Long Island group, Palawan Peninsula, and Mindoro Island. The presence of quartz grains and other minerals in the metamorphic rocks indicates a continental origin. Fossil evidence, such as nannofossils, has been used to date the rocks, revealing ages that correspond with specific geological periods. The study suggests that the Palawan micro continental block, along with the Long Island group, Mindoro, and other areas, broke off from the southern margin of mainland Asia. The rocks in these areas are similar in composition and age to those found in mainland Asia, providing evidence for their shared origin.

15:15

🎵 Conclusion on the Philippine Island Arc System

The script concludes by emphasizing the importance of continued research to refine the understanding of the Philippine island arc system's formation. The use of various methodologies and recent evidence has shed light on the geological history and the processes that contributed to the formation of the Philippines. This knowledge can also offer insights into the nature of geological hazards in the country. The final paragraph is filled with musical interludes and applause, suggesting a conclusion to a presentation or lecture on the topic.

Keywords

💡Philippine Island Arc System

The Philippine Island Arc System refers to the chain of islands in the Philippines, which is an island arc located southeast of the Asian landmass. It is a significant geological feature that has resulted from the tectonic activity at the margins of the Eurasian Plate and the Philippine Sea Plate. In the video, this system is central to understanding the country's geological history and its susceptibility to earthquakes and volcanic activity.

💡Subduction

Subduction is a geological process where one tectonic plate moves under another and sinks into the Earth's mantle. This process is key to the formation of the Philippine Island Arc System, as it is where the oceanic crust is forced under the continental crust, leading to volcanic activity and earthquakes. The script mentions subduction as a primary mechanism for the creation of the Philippine island arc.

💡Volcanoes

Volcanoes are vents in the Earth's surface from which lava, ash, and gases are being or have been erupted. The video script discusses the active, potentially active, and inactive volcanoes in the Philippines, which are a direct result of the subduction process. The Philippine Institute of Volcanology and Seismology monitors these volcanoes, indicating their importance to the country's geology.

💡Geologic Block

A geologic block refers to a segment of the Earth's crust that moves as a unit on the Earth's surface. The script mentions the collision of geologic blocks as part of the process that formed the Philippine Island Arc System. This concept is crucial for understanding the movement and interaction of tectonic plates in the region.

💡Trenches

Trenches are long, narrow depressions in the Earth's crust where the subduction of one tectonic plate beneath another occurs. The video script describes trenches as areas where the subduction process results in well conditions for earthquakes and volcanic activity, which are common in the Philippines.

💡Seismology

Seismology is the scientific study of earthquakes and the propagation of elastic waves through the Earth. The script refers to the Philippine Institute of Volcanology and Seismology, which monitors active volcanoes and earthquakes in the country. This field is vital for understanding and predicting seismic activities in the Philippine Island Arc System.

💡Metamorphic Rocks

Metamorphic rocks are formed when existing rock types undergo a transformation due to heat, pressure, or mineral exchange. The script mentions these rocks as part of the geology of the Philippine islands, indicating that they have been subjected to these transformative processes, which are often associated with tectonic activity.

💡Micro Continental Block

A micro continental block refers to a fragment of continental crust that has become separated from the main continental mass and is now part of an island arc system. The script discusses the Palawan micro continental block, which is believed to have originated from mainland Asia and collided with the Philippine mobile belt, contributing to the formation of the Philippine Island Arc System.

💡Fossils

Fossils are the preserved remains or traces of animals, plants, and other organisms from the past. The video script uses fossils as evidence to determine the age of rocks and their geological history. Fossils extracted from the rocks in the Zambales Peninsula, for example, indicate the age of the rocks and their connection to mainland Asia.

💡Geologic Mapping

Geologic mapping is the process of creating a map to show the distribution of rock types, structures, and other geological features. The script describes geologic mapping and geophysical surveys conducted on various islands, which are essential methods for understanding the geology and evolution of the Philippine Island Arc System.

💡Rock Composition

Rock composition refers to the types and proportions of minerals that make up a rock. The script discusses the composition of rocks found in different parts of the Philippines, such as the presence of quartz grains in metamorphic rocks, which are indicative of their origin from continental landmasses like mainland Asia.

Highlights

The Philippines is an island arc system located southeast of the Asian landmass, formed by the interaction of tectonic plates.

Geologic blocks and subduction of materials along trenches contribute to the formation of the Philippine island arc system.

The Philippine Institute of Volcanology and Seismology monitors 23 active volcanoes in the country.

The most active volcanoes are Mayon, Kanlaon, and Pinatubo, which are significant for geological studies.

The geologic configuration of the Philippine island arc system is influenced by its location between tectonic plates.

The Philippines experiences an average of 20 earthquakes daily due to its position on tectonic plate boundaries.

Several destructive earthquakes with magnitudes between 6.1 and 7.9 have devastated the country since the 1600s.

The 1968 Casiguran earthquake and the 1990 Luzon earthquake are examples of devastating seismic events.

The lack of earthquake reports in Palawan can be explained by its origin as a separate continental block.

The evolution of the Philippine island arc system began with the separation of a fragment from mainland Asia.

New methodologies and laboratory facilities have provided additional data for geological studies in the Philippines.

Geological mapping and geophysical surveys were conducted on remote island groups for further understanding.

Metamorphic rocks in the Long Island group suggest a connection to mainland Asia.

Fossil evidence from the Guru Agra Peninsula indicates a similar age and origin to other parts of the Philippine island arc.

Rock samples from Mindoro Island show a different geological history compared to other parts of the Philippine island arc.

Fossils and radiometric dating provide insights into the age and origin of the rocks in the Philippine islands.

The study of the Makati Island group shows different rock types, indicating a complex geological history.

The Philippine island arc system's formation is still under investigation, with ongoing studies to refine understanding.

Geological history and processes that contributed to the formation of the Philippines can inform about natural hazards.

Transcripts

[Music]

the Philippines an island arc system

located southeast of the Asian landmass

is trapped at the margins of the

Eurasian from the landfill where and the

Philippine Sea plate on the east the

immune sedimentary and metamorphic rocks

which make up the different islands in

the Philippines this metric complex

concepts which have referred a different

period throughout 53 and formation

comprising of more than 7500 island and

I'll induce the Philippine island arc

system was produced by the commission of

geologic block the collision is

subduction of special materials along

trenches results in well conditions

earthquakes and ventilation with a

fragment of the crust and after mental

on life on this figure we see the orange

triangles marking the locations of

active potentially active and inactive

volcanoes the Philippine Institute of

Volcanology and seismology monitors 23

active volcanoes throughout the country

the most active volcanoes are my own pal

can alone busan he book ebook

and pinatubo the geologic configuration

of the philippine island arc system

where it is found on both sides by

changes in the reason why we experience

a lot of earthquakes in the country

aside from trenches other potential

earthquake generators are active for the

most significant of which is that

anything also this can be traced from

the westernmost tip of Luzon Island in

the Ilocos Region through the coldest

weather it calculated into spoon then

both through the goals and exits in my

VW pal because of this earthquake

generators the Philippines experiences

on the average around 20 earthquake

daily but most of these are hardly

spells but are recorded by instruments

the different colored dots on the map on

the right show the location of Earth

with epicenters which have been recorded

since the 1600 the country has been

devastated by several destructive

earthquake with magnitudes between six

point one and seven point nine this is

was the earthquake that took place in

all the school 1968 with a magnitude 7.3

and whose epicenter was located in

custom wooden kettle

despite the distance of the earthquake

epicenters this must tell strongly in

Manila and led to the collapse of the

Ruby power in Bernardo a second

devastating earthquake was the world the

spot was on on July 15 1990 with a

magnitude of 7.9 its epicenter was

located near the tower resolve in the

right beehive

but the earthquake was felt in North and

Central Reserve we remember this

earthquake due to the devastation that

we saw in value particularly the

collapse of the Hyatt Hotel more

recently we witness the devastation

caused by the magnitude six point nine

earthquake which struck you will

non-immigrants Orion palace

several people died in barangay which

were very when the ground shaking

triggered landslides a year later on

October 15 2013

under sweet with the 7.2 magnitude trust

behold this caused the collapse and

destruction of several important

structures such as the nerve of church

now if we go back to the map that I

showed earlier it is worth noting that

we do not see any earthquakes reported

in Halawa

mmm this can be explained by the fact

the salawa

islands and several other islands which

are collectively called the Palau MX

continental block

we're not originally part into thinking

island arc system it originated

elsewhere before colliding with the rest

of the philippine island arc system

which geologists call the Philippine

mobile belt the palawan like a faulty

metal block used to be part of mainland

Asia the evolution of the philippine

island arc system began when this

fragment will fall from the southern

margin of mainland Asia the continental

margin begin field and led to the

formation of an oceanic crust this

failed margin of the Continental

landmass opened up to become the South

China Sea convenient opening on the

South China Sea

caused the broken off fragment to keep

southeastward

and eventually collided with a

Philippine mobile belt which was moving

northward although this collision

between the Palau micro continental bloc

and the Philippine mobile there is a

well-established aspect of affirmation

of the philippine island arc system it

is important to examine this in light of

improvements in technology and

development of new equipment this may

provide new data that will be useful in

understanding the evolution of the

philippine island arc system one thing

that geologists have to contend with

previously with the lack of data on the

ages of the rocks exposed in different

parts of the philippine island artistic

new methodologies in access to some

laboratory facilities have now provided

us with additional features for quality

fraud we also now have better equipment

for determining the composition of rocks

so for more than the decades now we have

focused our

on central Philippines in order to

collect more data that will help us

understand this aspect of the evolution

of the Philippine island art suspect our

study has taken us to the remote island

group which is made up of the black from

blown & shamian island geologic mapping

and geophysical surveys were carried out

along with the collection of rock

samples this were brought back to the

laboratory for various analysis among

the important features observed in the

long island group are the metamorphic

rocks which are characterized by the

presence of quartz minerals this for

each metamorphic rocks are believed to

have been derived from rocks

similar to those found in continental

land masses such as mainland Asia but we

use this new data as evidence to suggest

that their own blood I will group first

part of the following micro continental

block so together with a lava they make

up the fragments which broke off from

the southern margin of mainland Asia

after completing our investigations in

the Long Island proof our next

destination was the northwestern part of

Hawaii Island particularly the Guru Agra

Peninsula the results of our field

mapping various laboratory analysis and

physiological examination of their

example shows that the types of rocks

both in Vermont appear insular

are similar to those found in Halawa and

nearby islands the presence of fourth

grades in the sedimentary rocks is a

common feature in the rocks found in the

lung

and follower as mentioned earlier quite

the typical component aprox one in the

Continental landmass this new data that

supports earlier model the Galaga

Peninsula along with allowing Island use

some parts of mainland Asia

another result generated by our service

if the information provided by fossils

in the rocks in Rwanda Peninsula we were

able to extract nano fossils such as the

microscopic remains of regional areas

from some of the rock samples reveal

variants or protozoa which produced

delicious skeleton that may be preserved

in summation rocks lectures these are

the shapes chemical form and symmetry of

skeletal spine it is possible to

identify their species this is in turn

used to determine the age of the rocks

where they were found

because certain species flourish only

during specific ages or periods with

interest

history the regulary extracted from the

sample in Rwanda Peninsula northwestern

I indicate that this rocks are off

traffic each around 156 million years

ago the rock in Bhuvana peninsula north

- I share similar features same rock

similar composition with those that are

exposed in both lambda and allow an

island in similar Jurassic ish is

suggested by the degree to variance from

the sample although there are some

sections of this one vehicle on which

record even in other Egypt

approximately 200 to 207 million years

old from this result we provide new

evidence to show that one

it's also part of the palawan micro

fundamental block from Northwest tonight

we headed to the next target of our kill

campaign which is Mindoro Island

previous work by other researchers have

presented different ideas on the island

some researchers proposed the physics on

the southern maduro which is part of the

Microsoft mental fragment others however

argue that it is the entire island which

is of continental origin with our few

some things particularly Northwest

Medoro we collected rock samples from

examination under the microscope

sandstorms are dominantly made up of

quarks greens the metamorphic rocks also

show quartz grains and other minerals

which are typically observed in rocks

from the Continental landmass in

addition to the rocks and their

composition the focus obtained from the

limestone indicate an age of around 28

to 41 million years although much

younger than the ages of TV or the

sedimentary rocks in Palawan and blue on

the peninsula the sedimentary rocks in

Mindoro are still considerably older

than those found in the Philippine

mobile belt

aside from fossils we can also use their

funds to determine the ages of rocks

their sum is a mineral soil is abused

sentimentally and metamorphic rocks it

is resistant to heat and pollution and

country research in rock despite the

changes which rocks meander through

their concerns are useful in determining

the ages of rocks which contain them in

the case of the sample sample

Lauro the circle recorded regions of

approximately 185 to 196 million years

old

this means that the sample contains

fragments of old rock and when compared

to drops from other area this interest

are similar to the ages of rocks from

the southern part of mainland Asia with

this assault we propose that the whole

Mindoro island is also part of the

following micro continental block for

our next investigation we decided to go

towards the different sides of central

Philippines particularly by the islands

we distilled and other surveys to see if

we will see any similarities between the

wrapkin was bought the island with the

rocks that we saw in the area which we

previously investigated when the

must-buy besides sold for examined under

the microscope we did not see the quartz

grains which predominantly observed in

the side so samples from Halawa were one

gun and Mindoro the fossils extracted

from services was but a sedimentary

rocks correspondent well early/middle

micing age which is around 23 to 11.6

million years this were younger than the

rocks and in total in much younger than

that will drop in 11 and Rwanda because

of the different engine types of rocks

exposed in Makati island we were able to

conclude that Miss McAdam hand does not

form part of the flower micro-continent

ogloc although earlier studies have

previously described the Palau image

and a lot we have provided additional

data and new evidence from our recent

you some things to show that in addition

to palawan and this wonder the row

blonde island group Mindoro and burbank

appealing food are comprised of a lava

micro continental block in summary we

have a different aspects and deployed

various methodologies in order to

constrain the formations of the

philippine island arc system however

further studies must still be conducted

for us verifying our understanding of

how the philippines was born looking

back with geologic history and the

processes that contributed to its

formation can also provide insights on

the nature of the differentiy hazards in

the country

[Music]

and

[Music]

[Music]

[Applause]

[Music]

[Music]

you