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Posted: Thu Apr 03, 2025 2:58 am Post subject: Earthquake of March 28, 2025
Hi All,
The devastating earthquake that occurred on March 28 2025 at local time 11:50 am in Myanmar was of magnitude M7.7 and had a shallow focal depth of just 10 km. The epicentre was near the ancient city of Mandalay. As on date, over 2000 persons are dead and over 3900 injured in Myanmar.
Mandalay is the city where much of Amitav Ghosh's book,"The Glass Palace" which is an actual palace in the Mandalay Fort, is situated. Mandalay is a city steeped in history and mystique. I loved the city. I had been to Myanmar a few months after the March 24 2011, 6.3 Mw Shan earthquake and some of the devastation was still visible. It had struck me even then how that country has been, and will be devastated again and again by earthquakes, given its history, geography and construction practices. It is a country of primarily solid, heavy, masonry construction. I had seen little evidence of even the most rudimentary seismic resistant features in their construction. People there seemed to be very fatalistic. "Whatever willbe, will be".
As per USGS, "the March 28, 2025,M7.7 earthquake near Mandalay, Burma (Myanmar), occurred as the result of strike slip faulting between the India and Eurasia plates. The finite fault solution indicates the size of the March 28, 2025 event is about 200 km by 20km (length x width)… This region has experience similar large strike slip earthquakes, with six other magnitude 7 and larger earthquakes occurring with about 150 miles (250 km) of the March 28, 2025 earthquake since 1900. The most recent of these was a magnitude 7.0 earthquake in January 1990, which caused 32buildings to fall. A magnitude 7.9 earthquake occurred south of today's earthquake in February 1912. Within this broad zone of tectonic deformation,other large earthquakes, including a magnitude 7.7 earthquake in 1988, have caused dozens of fatalities."
Parts of Myanmar, and specifically the area around Mandalay, have been built and rebuilt many times after earthquakes. The Shwedagon Pagoda in Yangon, for example, (The Global Vipassana Pagoda in Mumbai is a replica of the Shwedagon Pagoda), said to be 2500 years old(!) has been rebuilt in recorded history numerous times following damage caused by earthquakes. The worst damage was caused by a 1768earthquake that brought down most of the top of the stupa...A moderate earthquake in October 1970 also caused significant damage. Serendipitously this pagoda does not seem to have undergone much damage in the 2025 earthquake but another large pagoda, Shwe Sar YanPagoda lost its topmost parts.
Another city frequently affected by earthquakes is the ancient city of Bagan. Bagan is one of the most beautiful historical sites you can visit. Between 1000 AD and 1250 AD, Bagan's rulers and its wealthy residents constructed over 10,000religious monuments (approximately 1000 stupas, 10,000 small temples and 3000monasteries) in an area of 104 km2 (40 sq mi)in the Bagan plains. Bagan is located in central Myanmar and has suffered from over 400 recorded earthquakes between1904 and 1975. An M7 earthquake occurred on 8 July 1975 near Mandalay, that damaged thousands of temples and pagodas severely and irreparably in Bagan. Today, only 2229 temples and pagodas of the over 10,000 built remain. Most recently, Bagan had sustained heavy damage in the 2016earthquake (M6.9). Bagan is a UNESCO Heritage Site spread with small and big pagodas and stupas (and nothing else) as far as the eyes can see. The March 2025 earthquake epicentre was only 10 miles from Sagaing, which is next to Bagan. I will not be surprised if once again, Bagan heritage has been badly destroyed in the earthquake.
The damage and collapse of buildings in Myanmar caused by the March 28 2025 earthquake is available on social media and at many sites on the internet. But due to the damage and disruption of communication and transportation, the extent of damage and destruction in Myanmar is not fully known.
One building of note in Mandalay to have collapsed is the 11-storey Sky Villa Condominium complex which had a rooftop bar and a modern gym. The failure of this multistorey building happened gradually, unlike the tower in Bangkok.
What has captured the imagination of structural engineers and laypersons worldwide is the collapse of a 30+storey tower, not yet fully completed, in Bangkok. The city of Bangkok is located more than 1,000 km from the epicentre of Friday's earthquake. Here we were, shouting from the rooftops that tall buildings are not generally affected significantly by earthquakes; this collapse has collapsed this delusion that everyone has been carrying. This reminded me of the M8 1985 Mexico City earthquake in which buildings between 6 to 15 storeys (mostly flat slab and waffle slab buildings) collapsed/ were badly affected due to the soil effects (primarily amplification of ground motion) from an earthquake who's epicentre was about 350 km away – Mexico city is famously sited on an old lakebed basin of volcanic ash and clay. Bangkok too is similarly situated on soft Bangkok clay, and even though it lies ata significant distance from any known active fault, due to Bangkok clay soils' proclivity to amplify certain ground motions, it is at risk of strong ground shaking from far-site earthquakes.
And yet it was one, just one, major building that collapsed (and connecting bridges of towers that got disconnected).The building pancaked, as it were, in a matter of seconds. The building displayed no ductile behaviour, the failure was brittle. I watched the failure in slow motion many times and what struck me was how the columns at the stilt level sheared off, like a clean knife-cut. Where was the reinforcement?
Bangkok Tower: Notice the shearing off of the columns
I think there is much to talk about this failure and I would like you to watch it carefully. Where did the failure initiate? What kind of failure was it? Was it a failure of the couplers? Or something else? Why did the core also come tumbling down?
Posted: Thu Apr 03, 2025 4:30 am Post subject: Earthquake of March 28, 2025
Very well explained, Alpaji Thanks Rangarao V V
Ph.D (Strl Engg, IITH)
SL STRUCTURAL CONSORTIUM
040 66669766
Quote:
On 3 Apr 2025, at 8:33 AM, alpa_sheth <forum@sefindia.org> wrote:
 Hi All,
The devastating earthquake that occurred on March 28 2025 at local time 11:50 am in Myanmar was of magnitude M7.7 and had a shallow focal depth of just 10 km. The epicentre was near the ancient city of Mandalay. As on date, over 2000 persons are dead and over 3900 injured in Myanmar.
Mandalay is the city where much of Amitav Ghosh's book,"The Glass Palace" which is an actual palace in the Mandalay Fort, is situated. Mandalay is a city steeped in history and mystique. I loved the city. I had been to Myanmar a few months after the March 24 2011, 6.3 Mw Shan earthquake and some of the devastation was still visible. It had struck me even then how that country has been, and will be devastated again and again by earthquakes, given its history, geography and construction practices. It is a country of primarily solid, heavy, masonry construction. I had seen little evidence of even the most rudimentary seismic resistant features in their construction. People there seemed to be very fatalistic. "Whatever willbe, will be".
As per USGS, "the March 28, 2025,M7.7 earthquake near Mandalay, Burma (Myanmar), occurred as the result of strike slip faulting between the India and Eurasia plates. The finite fault solution indicates the size of the March 28, 2025 event is about 200 km by 20km (length x width)… This region has experience similar large strike slip earthquakes, with six other magnitude 7 and larger earthquakes occurring with about 150 miles (250 km) of the March 28, 2025 earthquake since 1900. The most recent of these was a magnitude 7.0 earthquake in January 1990, which caused 32buildings to fall. A magnitude 7.9 earthquake occurred south of today's earthquake in February 1912. Within this broad zone of tectonic deformation,other large earthquakes, including a magnitude 7.7 earthquake in 1988, have caused dozens of fatalities."
Parts of Myanmar, and specifically the area around Mandalay, have been built and rebuilt many times after earthquakes. The Shwedagon Pagoda in Yangon, for example, (The Global Vipassana Pagoda in Mumbai is a replica of the Shwedagon Pagoda), said to be 2500 years old(!) has been rebuilt in recorded history numerous times following damage caused by earthquakes. The worst damage was caused by a 1768earthquake that brought down most of the top of the stupa...A moderate earthquake in October 1970 also caused significant damage. Serendipitously this pagoda does not seem to have undergone much damage in the 2025 earthquake but another large pagoda, Shwe Sar YanPagoda lost its topmost parts.
Another city frequently affected by earthquakes is the ancient city of Bagan. Bagan is one of the most beautiful historical sites you can visit. Between 1000 AD and 1250 AD, Bagan's rulers and its wealthy residents constructed over 10,000religious monuments (approximately 1000 stupas, 10,000 small temples and 3000monasteries) in an area of 104 km2 (40 sq mi)in the Bagan plains. Bagan is located in central Myanmar and has suffered from over 400 recorded earthquakes between1904 and 1975. An M7 earthquake occurred on 8 July 1975 near Mandalay, that damaged thousands of temples and pagodas severely and irreparably in Bagan. Today, only 2229 temples and pagodas of the over 10,000 built remain. Most recently, Bagan had sustained heavy damage in the 2016earthquake (M6.9). Bagan is a UNESCO Heritage Site spread with small and big pagodas and stupas (and nothing else) as far as the eyes can see. The March 2025 earthquake epicentre was only 10 miles from Sagaing, which is next to Bagan. I will not be surprised if once again, Bagan heritage has been badly destroyed in the earthquake.
The damage and collapse of buildings in Myanmar caused by the March 28 2025 earthquake is available on social media and at many sites on the internet. But due to the damage and disruption of communication and transportation, the extent of damage and destruction in Myanmar is not fully known.
One building of note in Mandalay to have collapsed is the 11-storey Sky Villa Condominium complex which had a rooftop bar and a modern gym. The failure of this multistorey building happened gradually, unlike the tower in Bangkok.
What has captured the imagination of structural engineers and laypersons worldwide is the collapse of a 30+storey tower, not yet fully completed, in Bangkok. The city of Bangkok is located more than 1,000 km from the epicentre of Friday's earthquake. Here we were, shouting from the rooftops that tall buildings are not generally affected significantly by earthquakes; this collapse has collapsed this delusion that everyone has been carrying. This reminded me of the M8 1985 Mexico City earthquake in which buildings between 6 to 15 storeys (mostly flat slab and waffle slab buildings) collapsed/ were badly affected due to the soil effects (primarily amplification of ground motion) from an earthquake who's epicentre was about 350 km away Mexico city is famously sited on an old lakebed basin of volcanic ash and clay. Bangkok too is similarly situated on soft Bangkok clay, and even though it lies ata significant distance from any known active fault, due to Bangkok clay soils' proclivity to amplify certain ground motions, it is at risk of strong ground shaking from far-site earthquakes.
And yet it was one, just one, major building that collapsed (and connecting bridges of towers that got disconnected).The building pancaked, as it were, in a matter of seconds. The building displayed no ductile behaviour, the failure was brittle. I watched the failure in slow motion many times and what struck me was how the columns at the stilt level sheared off, like a clean knife-cut. Where was the reinforcement?
Bangkok Tower: Notice the shearing off of the columns
I think there is much to talk about this failure and I would like you to watch it carefully. Where did the failure initiate? What kind of failure was it? Was it a failure of the couplers? Or something else? Why did the core also come tumbling down?
Posted: Thu Apr 03, 2025 6:30 am Post subject: Earthquake of March 28, 2025
Sorry!
Do we really opt the right to be on Earth.
See our knowledge base ratio to Our Rat Race.
I know this platforms full of dignitaries.
But we always forget we have merely 6' long body whose longevity suitably differs from 50 years to 140 years.
We made suitable cage prison for the old age that is our reasearch gist multistorey building.
We when step in the world of microbiology we tried to add living organisms in concrete.
And we should count on our finger our duties...
1st : live happily
2nd: live longer
3rd: live peacefully
4th: need adequate food
5th: need adequate sleep.
God is great, think tomorrow if it there paddy or grains we have to have from space station cultivation what we do.
You can say petroleum we dig out and run vehicle industry.
Don't read my reply, 97% of us only knows how to grab and shout.
Don't Read me, please.
The article is a worthy one, which will keep a positive step for tomorrow's mankind to be on earth, safely.
On Thu, 3 Apr, 2025, 11:15 AM venkatarangarao, <forum@sefindia.org (forum@sefindia.org)> wrote:
[quote] Very well explained, Alpaji Thanks Rangarao V V
Ph.D (Strl Engg, IITH)
SL STRUCTURAL CONSORTIUM
040 66669766
Posted: Thu Apr 03, 2025 8:30 am Post subject: Earthquake of March 28, 2025
Thanks a lot Mam for your detail and educatuve information.
Let us hear from other experts in this subject.
On Thu, 3 Apr 2025, 10:03 venkatarangarao, <forum@sefindia.org (forum@sefindia.org)> wrote:
[quote] Very well explained, Alpaji Thanks Rangarao V V
Ph.D (Strl Engg, IITH)
SL STRUCTURAL CONSORTIUM
040 66669766
The slow motion video shows abrupt snapping of two columns as if it lacked ductility in reinforcement , acting as trigger for progressive collapse within seconds.
Lets discuss this in detail.
Best regards
Sanjeev Kumar
Admin SEFI
[quote="sangramiitk"]Sir,Can we have the link of the video of shearing of these stilt floor columns and pre vibration of buildings..
Best Regards
-Sangram Kesari Das
On Thu, Apr 3, 2025 at 10:01 AM venkatarangarao <forum> wrote:
Quote:
Very well explained, Alpaji Thanks Rangarao V V
Ph.D (Strl Engg, IITH)
SL STRUCTURAL CONSORTIUM
040 66669766
Earthquake of 7.7 R and after shocks ranging from 4.5 R to 7.0 R in Myanmar with epicenter only 10 km down
It was highly devastating EQ causing death snd injuries to large population, especially in Mandalay . Bankok situated 1000 km away also suffered - one building under construction came down.
Main reasons can be summarised as under :-
A) Mandalay city and nearby
I) This is located on Fault line and it had experienced EQs of 7.0 many times due to movement of plates.
ii) FOUNDATION STATA :- As per local experts on TV , the soil is prone to LIQUIFACTION .Some 3 to 4 stories structures got tilted whereas In other cases of high rise buildings got sheared off through foundation soil causing further failure of superstructure. The videos show vertical downing of high rise buildings, first - indicate Soil strata causing Local shear failure predominantly.
iii) CREATION OF STILTS AT GROUND STOREY
This is not a better planning of structure - stilts must be created within basement storey/s. The extent of 2.5 times or More effect of EQ forces in stilt columns and beams need to be taken as per local EQ codes.
However Basement - the Retaining walls at periphery relieve this effect but stilt columns there, still, need to be designed for minimum 40 percent or More forces on stilt columns ( assuming no walls).
iv) FLAT SLAB FLOORS CONSTRUCTION SHALL BE TOTALLY AVOIDED IN ZONES III, IV AND V ,,
It is seen that Structure Consultants oblige Architects for Flat slsb construction which is very risky in EQ severe Zones.
v) STEEL REINFORCEMENT MUST CONFORM TO STANDARDS AS REGARDS ALL PARAMETERS TO HAVE SUFFICIENT DUCTILE STRENGTH INCLUDING DUCTILE PROVISIONS TO AVOID COLLAPSE OF STRUCTURE S.
I think Mandalay devastation is more related TO SOIL FOUNDATION THAN SUPERSTRUCTURE STRENGTH. Any Structurally strong structure can fail if it's Foundation soil gives way.
B) Bankok Building Collapse
This seems - failure occured at stilt columns ( already dealt above
Just my layman Observation - need to be ignored if otherwise
HOWEVER
We must focus on corrective actions for better design / construction.
As regards Buildings on Pile foundation suffering collapse
MANDALAY CITY
Due to Liquefaction of soil - following effects causing failure of piles foundation :-
I) The carrying capacity of piles greatly reduced as Liquified depth zone do not provide any skin friction to piles
ii) The depth of pile fixity goes further deeper beneath Liquified zone causing much higher moments in piles requiring very high reinforcement . To some extent ductility takes care but increase in depth of fixity create enormous deficiency in provided reinforcement of piles.
FOR FOUNDATIONS ON RAFT :
Already explained regarding Local shear failure in LIQUIFIED Zone causing downing of building as whole or Tilting of structure.
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