SEISMIC Engineering Analysis of the March 28, 2025, Magnitude 7.7 Earthquake in Myanmar

GREG LOWITZ, BUILDERA

Author’s Note

In the immediate aftermath of a major earthquake, technical data and casualty figures often evolve. This analysis reflects the best available data at the time of publication and may be revised as new information emerges.​

Abstract

On March 28, 2025, a magnitude 7.7 earthquake struck central Myanmar at a shallow depth of 10 kilometers, approximately 14.2 km NNW of Sagaing. The quake occurred along the active right-lateral strike-slip Sagaing Fault, located between the converging Indian and Sunda plates. The quake generated violent ground motions across Myanmar, triggering catastrophic structural failures over 1,029 km (639 miles) away in Bangkok’s Chatuchak District.

As of March 29, 2025, Myanmar’s military junta confirmed at least 1,644 fatalities, with thousands more injured. The death toll is expected to rise as access improves to remote villages. In Bangkok, the collapse of a 33-story office tower under construction resulted in at least 10 deaths, with dozens more injured or unaccounted for. The failure has drawn international attention to the seismic vulnerability of high-rise structures in areas not typically considered high-risk.

This article presents a detailed seismic analysis using data from the United States Geological Survey (USGS), including macroseismic intensity mapping and peak ground motion observations. Construction vulnerabilities in Myanmar and Thailand are assessed, along with the implications for regional seismic resilience. The findings underscore the urgent need for improved design standards and structural monitoring following major earthquakes—particularly in high-rise or soft-soil settings—to detect cracking, differential settlement, and latent damage made worse by aftershocks.

1. Introduction

At 12:50:52 MMT (06:20:52 UTC) on March 28, 2025, a magnitude 7.7 earthquake struck Myanmar's central Sagaing region near Mandalay. According to the United States Geological Survey (USGS), the epicenter was located approximately 14.2 km NNW of Sagaing at a depth of 10.0 km—making this a shallow crustal event with high potential for destructive ground motions.

The mainshock occurred along the right-lateral Sagaing Fault, an active strike-slip fault that accommodates the northward movement of the Indian Plate relative to the Sunda Plate. As one of the most prominent seismic features in Southeast Asia, the Sagaing Fault has a documented history of large earthquakes, including major events in 1931 (Mw 7.6 - USGS) and 1956 (Mw 6.8 - USGS), both of which impacted central Myanmar. The fault traces a path from the Andaman Sea in the south through Myanmar’s major population centers, including Yangon, Nay Pyi Taw, and Mandalay, making it a key concern in regional seismic hazard modeling.

Initial USGS ground motion models and contemporaneous self reporting suggested extremely strong shaking near the epicenter and along parts of the fault, with Modified Mercalli Intensity (MMI) values of IX (Violent) projected in the hardest-hit zones. At a shallow depth of only 10 kilometers, the earthquake's seismic energy was released close to the Earth's surface, significantly amplifying its destructive potential.

Myanmar’s seismic infrastructure is not adequately prepared for such events. Many buildings, especially in rural areas and older urban districts, are constructed of unreinforced masonry or concrete block without adherence to modern seismic codes. These deficiencies, combined with the high population density in regions near the Sagaing Fault, contributed to widespread damage and loss of life.

In addition to the devastation within Myanmar, the 2025 quake caused unexpected structural failures in Bangkok, Thailand—roughly 1,029 km (639 miles) from the epicenter. A 33-story reinforced concrete office tower under construction collapsed during the quake, resulting in growing fatalities and raising urgent questions about the vulnerability of high-rise structures subjected to long-period ground motions transmitted over long distances.

This article provides a detailed examination of the 2025 Myanmar earthquake through analysis of USGS data, seismic intensity maps, ground motion predictions, and structural performance observations. It also emphasizes the need for widespread post-event structural monitoring—especially in high-rise developments and areas with soft-soil amplification—to identify hidden damage, assess settlement risk, and prepare for aftershock vulnerability.

2. Seismotectonic Setting and USGS Data Analysis

2.1 Tectonic Framework

The March 28, 2025, magnitude 7.7 earthquake occurred along the central segment of the Sagaing Fault, a major right-lateral strike-slip fault system that accommodates the relative motion between the Indian and Sunda tectonic plates. This boundary zone, which runs north–south through central Myanmar, plays a key role in regional plate tectonics and is one of Southeast Asia’s most active fault systems.

Geodetic studies have shown that the Indian Plate is moving northward at approximately 40–50 mm/year relative to the Eurasian Plate. A portion of this convergence is absorbed by crustal deformation along the Himalayas, while the remainder is partitioned into lateral motion across the Sagaing Fault. Specifically, the Sagaing Fault accommodates around 18 to 20 mm/year of right-lateral slip, as measured by continuous GPS monitoring. This rate of motion places considerable strain on the fault system, contributing to its history of large and damaging earthquakes.

The Sagaing Fault extends for more than 1,200 km from the Andaman Sea in the south to the eastern Himalayan syntaxis in the north. It bisects Myanmar and passes near major population centers including Yangon, Bago, Nay Pyi Taw, Mandalay, and Myitkyina. The proximity of this fault to so many urban areas makes it a significant seismic hazard.

This particular earthquake occurred on a well-known segment of the fault near Sagaing Township. Historical seismicity in the area includes the 1931 Mw 7.6 earthquake and the 1956 Mw 6.8 event, both of which caused extensive damage in central Myanmar. The recurrence of large-magnitude events along this stretch reinforces the notion that strain is not being released gradually but rather in large episodic ruptures.

Tectonically, this section of Myanmar lies within a complex zone of deformation shaped by the interaction of three major plates: the Indian Plate, the Sunda Plate, and the Eurasian Plate. While subduction occurs offshore to the west along the Arakan Trench, inland deformation is characterized primarily by strike-slip motion and crustal block rotations. The Sagaing Fault plays a dominant role in accommodating these forces, with localized complexities that include restraining bends, releasing steps, and fault segmentation.

These structural nuances may have contributed to the characteristics of the 2025 earthquake rupture. Further analysis of the focal mechanism and slip distribution will help clarify the degree to which fault geometry influenced rupture propagation and ground motion amplification.

2.2 Summary of Key USGS Earthquake Parameters

• Date and Time: March 28, 2025, 12:50 local time (06:20 GMT).

• Location: 22.00°N, 95.93°E, 14.2 km NNW of Sagaing.

• Magnitude: Mw 7.7, with an estimated rupture length of 100-200 km (Wells and Coppersmith 1994).

• Depth: 10 km (shallow).

• Focal Mechanism: Right-lateral strike-slip, strike ~355°, dip ~85°.

• Aftershocks: Mw 6.4 at 11 minutes post-mainshock, plus multiple Mw 4.5-5.5 events within 100 miles (USGS 2025).

2.3 Ground Motion Characteristics and Modified Mercalli Intensity (MMI)

Limited USGS data indicates PGA exceeding 0.5-1.0 g near the epicenter, attenuating to 0.01 g in Bangkok (>1,000 km away). Modified Mercalli Intensity (MMI) reached VIII-IX near Mandalay and IV-V in Bangkok. Spectral acceleration at 0.2 seconds (Sa0.2s) likely surpassed 1.0 g near-field, with significant low-frequency energy propagating far due to the shallow source and regional geology (Boore et al. 2014).

2.4 USGS Ground Motion and Intensity Maps

The USGS released multiple critical maps for the March 28, 2025, Myanmar earthquake, including but not limited to: the Macroseismic Intensity Map, the Peak Ground Acceleration (PGA) Map, and the Peak Ground Velocity (PGV) Map. All were processed on March 29, 2025, at 19:19:31 UTC (Version 11) (USGS 2025).

• Macroseismic Intensity Map: The Modified Mercalli Intensity (MMI) reached VIII–IX (severe to violent shaking) near Mandalay, V–VI (moderate to strong shaking) in Chiang Mai, and IV–V (light to moderate shaking) in Bangkok and surrounding regions. These intensity levels underscore the far-reaching effects of the shallow quake, with long-period surface waves sustaining damaging energy over distances exceeding 1,000 km.

• Peak Ground Acceleration (PGA) Map: PGA values reached 50–100% g (0.5–1.0 g) near the epicenter, attenuating to 20–50% g (0.2–0.5 g) around Nay Pyi Taw, and further declining to 1–2% g (0.01–0.02 g) in Bangkok. These values align with observed structural damage patterns and highlight the intensity of shaking across central Myanmar.

• Peak Ground Velocity (PGV) Map: PGV values likely exceeded 100 cm/s within 20 km of the epicenter, decreased to 5–10 cm/s near Nay Pyi Taw, and ranged from 1–2 cm/s in Bangkok. While PGV in Bangkok was relatively low, it was sufficient to trigger long-period resonance in tall buildings, amplifying structural response—a phenomenon consistent with observations from Worden et al. (2012).

2.5 Prediction vs. Observation of Ground Motion

The USGS "Prediction and Observations" chart compares predicted Peak Ground Acceleration (PGA) values, derived from Ground Motion Prediction Equations (GMPEs), with observed PGA data from seismic stations (DYFI stations) and reported intensities (USGS 2025). The chart plots PGA (in %g) against rupture distance (in kilometers) on a log-log scale. It includes the following elements:

• Purple Line and Shaded Area: Represents the median predicted PGA and its ±1 standard deviation range, as calculated from the GMPE (Boore et al., 2014).

• Red Dot (IX MMI): Indicates the inferred PGA at the epicenter, approximately 118% g (1.18 g) at a distance of 1.9 km.

• Orange Dot (VIII MMI): Shows the inferred PGA near the epicenter, around 76% g (0.76 g) at a distance of 3.7 km.

• Blue/Green/Yellow Dots (DYFI Stations/Reported Intensity MMI): Display multiple inferred PGA values based on "Did You Feel It?" (DYFI) reports, reflecting observed shaking intensities.

• Blue Triangles (Seismic Stations): Represent measured PGA at various locations and distances, including Yangon and Keng Tun in Myanmar, and Chiang Mai in Thailand.

2.6 Discrepancies Between Observed and Predicted Ground Motions

Ground motion observations from the March 28, 2025, Myanmar earthquake reveal significant discrepancies with the predictions made by the Ground Motion Prediction Equation (GMPE) of Boore et al. (2014). These differences vary by distance range, with varying implications for model accuracy and applicability in the region.

Near-Field (0–200 km):

Only two recorded data points fall within the near-field range. At 2 km from the epicenter, PGA was measured at 118% g, aligning well with the GMPE-predicted median of ~100% g. A second observation at 3.7 km yielded 76% g, also consistent with expected values. However, no additional observations exist between 4 km and 200 km—whether from seismic stations, DYFI responses, or intensity reports. This data gap severely limits the ability to validate GMPE performance across the broader near-field zone.

The absence of data likely reflects sparse instrumentation, low population density, and logistical challenges in central Myanmar. Although the model performs well at very short distances, comprehensive validation in the near-field is currently not possible. Future hazard assessments would benefit from an expanded seismic network to address this limitation.

Intermediate Distances (200–300 km):

The first significant cluster of ground motion data appears at distances between 200 and 300 km, particularly near Nay Pyi Taw (~220 km). Observed PGA values range from 2.9% g to over 10% g, substantially exceeding the GMPE-predicted median of ~2% g and falling largely outside the expected ±1σ range (~1–3% g). This persistent overprediction extends out to 265 km, indicating that the GMPE underestimates ground motions in this intermediate range.

High variability in this zone may be attributed to site amplification, reporting inconsistencies, or instrument sparsity. Notably, Nay Pyi Taw lies along the rupture trace and appears to have experienced disproportionately strong shaking compared to other areas at similar distances. This could be due to rupture directivity, fault geometry, or localized amplification effects, suggesting regional complexities not well captured by the current GMPE.

Far-Field (300–1000 km):

At around 700 km, observed PGA values range from 1.6% g to 7.6% g, far exceeding the predicted median of ~0.05% gand the ±1σ envelope (~0.1% g). Although no direct station data are available at Bangkok (965 km), prior sections (see 2.4 and 4.4) cite USGS-derived PGA estimates of 1–2% g, versus GMPE predictions of just ~0.005% g.

This underprediction grows with distance and highlights the GMPE’s limited ability to account for efficient low-frequency wave propagation from shallow strike-slip events. The earthquake’s shallow depth (10 km) and rupture orientation produced long-period surface waves that traveled with minimal attenuation across the Indo-Burman Range and Thai peneplain. Additionally, the soft, water-saturated soils in Bangkok’s Chao Phraya Basin (Vs30 < 180 m/s) further amplified shaking, increasing PGA by a factor of 2–3.

2.7 Model Limitations and Regional Effects

The GMPE by Boore et al. (2014) was developed from a global dataset and assumes generic site conditions (e.g., Vs30 = 760 m/s for rock). It does not account for the unique attenuation properties of the Sagaing Fault, the sediment-filled Central Myanmar Basin, or the soft alluvium of the Chao Phraya Basin in Thailand. These site and path effects are critical to understanding ground motion response in this region.

Observed PGAs in the intermediate (200–300 km) and far-field (700–965 km) zones consistently exceed model predictions by wide margins. These discrepancies indicate that the existing GMPE lacks regional calibration and underrepresents amplification and waveguide effects. Incorporating local geotechnical and geological parameters into new or adjusted GMPEs is essential to improving hazard modeling in mainland Southeast Asia.

2.8 Implications

The GMPE’s consistent underprediction of PGA at intermediate and far-field distances—particularly at 200–300 km, 700 km, and 1,000 km—has critical implications for seismic risk assessment. For example, the collapse of the Bangkok skyscraper has been partially attributed to reliance on Thailand’s seismic code (DPT 1302-52), which was based on underestimated PGA values of 0.1–0.15 g. This highlights an urgent need for the following improvements:

• Development of region-specific GMPEs calibrated to the tectonic and geological characteristics of Myanmar and Thailand

• Enhanced attenuation models that better account for long-period wave propagation through rigid crustal waveguides

• Integration of site-specific amplification factors for urban centers, particularly those built on soft, unconsolidated sediments

Such refinements are essential for improving the accuracy of seismic hazard assessments and for guiding resilient infrastructure design across mainland Southeast Asia.

3. Historical Context of Earthquakes in Myanmar

3.1 Seismic History Along the Sagaing Fault

The Sagaing Fault, a dominant right-lateral strike-slip feature in Myanmar’s tectonic framework, has a well-documented history of major earthquakes. It serves as a primary strain-release mechanism between the Indian and Sunda Plates.

One of the most significant historical events occurred on July 5, 1930: the Mw 7.3 Bago earthquake. This event ruptured approximately 100–150 km of the fault near its southern terminus, close to present-day Yangon (then Rangoon). It produced Modified Mercalli Intensity (MMI) levels up to VIII and resulted in approximately 500 fatalities, primarily due to the collapse of unreinforced colonial-era buildings in the densely populated Bago region. Liquefaction along the Bago River delta further exacerbated the destruction, sinking buildings and disrupting water supplies.

On August 31, 1946, a Mw 7.6 earthquake struck the northern segment of the fault near Tagaung, about 200 km north of Mandalay. One of the largest recorded events on the Sagaing Fault, it ruptured over 200 km and triggered landslides that blocked the Ayeyarwady River, causing upstream flooding. With a hypocentral depth of 15–20 km, it killed more than 1,200 people. However, the relatively sparse population in the rugged northern region limited the human toll compared to urban events.

The July 16, 1956, Mw 6.8 Mandalay earthquake, centered just 20 km southwest of the city, was shallower (approximately 8 km deep) and more localized, with a rupture length of about 50 km. It damaged Mandalay’s historic pagodas and caused around 40 deaths. Shaking at MMI VII toppled weaker structures but spared much of the city due to the quake’s moderate magnitude.

Other notable events include the 1991 Mw 7.0 earthquake near Thabeikkyin and the 2012 Mw 6.8 event near Shwebo, both underscoring the fault’s recurring seismic activity.

The March 28, 2025, Mw 7.7 earthquake stands apart from all its predecessors due to its exceptional magnitude, a 350-km rupture length, and far-reaching effects—including unprecedented shaking as far away as Bangkok. It marks a new benchmark in the seismic legacy of the Sagaing Fault.

3.2 Comparison to the 2025 Event

The March 28, 2025, Mw 7.7 earthquake exceeds all previous Sagaing Fault events in both scale and impact, driven by its shallow 10-km depth, higher magnitude, and extensive rupture dynamics.

In contrast to the 1930 Bago quake (Mw 7.3), which affected a densely populated area but ruptured only 100–150 km of the fault, the 2025 event ruptured 350 km, from Thabeikkyin to south of Yamethin. According to USGS estimates, the event released energy equivalent to approximately 1,400 Hiroshima-sized atomic bombs (2.0 × 10¹⁶ joules).

This extended rupture was facilitated by the fault’s straight geometry, allowing peak ground accelerations (PGA) to exceed 0.8 g near Mandalay—far surpassing the 0.4–0.5 g recorded in Bago in 1930. As a result, both modern and traditional structures were demolished, and widespread liquefaction occurred across the Ayeyarwady floodplain.

Although the 1946 Mw 7.6 northern quake was comparable in magnitude, it struck at a deeper depth (15–20 km) in a sparsely populated region, limiting its impact radius. Its MMI VIII shaking dissipated before reaching major cities like Mandalay or Yangon. In contrast, the 2025 earthquake’s shallow focus amplified surface wave energy, sustaining destructive MMI IX shaking across central Myanmar and generating long-period surface waves that propagated more than 600 miles to Bangkok—where MMI VI shaking caused the collapse of a high-rise building. Such long-range impacts were unprecedented in prior events.

The 1956 Mw 6.8 Mandalay earthquake, while shallow and near the city, lacked the magnitude and rupture length to cause similar devastation. Its effects dissipated within a 50-km radius.

USGS intensity maps for the 2025 event show a damage footprint far exceeding those of earlier earthquakes. Shaking intensities of MMI VII–VIII extended over 200 km from the epicenter, driven by a peak slip of 6.48 meters (per the USGS finite fault model). The Prediction and Observations chart (USGS 2025) further highlights this anomaly: modeled fatalities exceed 10,000, in stark contrast to the hundreds killed in past events.

This higher toll reflects present-day conditions—Myanmar’s rapid urban growth, widespread use of fragile construction materials, and civil war-induced vulnerabilities—factors absent during earlier earthquakes. Moreover, Bangkok’s unexpected and severe shaking, amplified by soft deltaic soils, underscores how the 2025 earthquake’s combination of magnitude and shallow depth projected its impact over an extraordinary range.

4. Building Construction Practices and Damage Assessment

4.1 Myanmar Construction

In Myanmar, the building stock predominantly comprises traditional unreinforced masonry (URM)—typically brick or stone with mud mortar—and lightly reinforced concrete (RC) frames. Both are notoriously vulnerable to seismic loads due to inadequate ductility and lateral resistance.

URM structures, common in rural areas and older urban neighborhoods like Mandalay, lack tensile reinforcement. This makes them especially prone to brittle failure under cyclic loading, as evidenced by widespread collapses during the March 28, 2025, Mw 7.7 earthquake. Lightly reinforced RC frames—often found in mid-20th-century construction—frequently omit critical seismic detailing, such as confinement stirrups, strong-column/weak-beam configurations, and integrated shear walls. These omissions significantly increase the risk of soft-story collapse and rebar pullout during strong ground motion.

The Myanmar National Building Code (MNBC 2016), which is partly based on Eurocode 8 principles, mandates a design Peak Ground Acceleration (PGA) of 0.3–0.4 g (30–40% g) for Zone 3 areas like Mandalay. This corresponds to a 475-year return period (10% probability of exceedance in 50 years). For Type C soil (soft rock or stiff soil, Vs = 180–360 m/s), MNBC’s response spectrum translates this to a spectral acceleration (Sa) of approximately 0.75–1.0 g at short periods (0.2 s).

However, enforcement of the code remains inconsistent, hindered by limited resources, systemic corruption, and the ongoing civil war since 2021. As a result, many new buildings are non-compliant, and older ones remain unretrofitted.

According to USGS data, the 2025 earthquake produced a PGA exceeding 0.8 g near the epicenter (Modified Mercalli Intensity IX), with recorded values of 0.5–0.6 g in Mandalay—well above MNBC design thresholds. This exceedance, combined with the earthquake’s shallow 10-km depth and a 350-km rupture length that amplified surface shaking, overwhelmed even some code-compliant structures.

4.2 Thailand Construction (Bangkok)

Bangkok’s modern high-rise skyline relies heavily on reinforced concrete (RC) frames, designed according to the Thai seismic standard DPT 1302-52 (updated in 2009). This standard reflects the city’s classification as a low-to-moderate seismic zone and is aligned with ASCE 7-05 principles. It specifies a design Peak Ground Acceleration (PGA) of 0.1–0.15 g (10–15% g) for a 475-year return period, corresponding to a spectral acceleration (Sa) of 0.25–0.375 g at 0.2 seconds for Site Class D (stiff soil, Vs = 180–360 m/s).

However, Bangkok’s actual subsoil consists of soft alluvial deposits from the Chao Phraya delta, classified as Site Class E (Vs < 180 m/s). These conditions amplify ground motions, often doubling the PGA to 0.2–0.3 g during distant seismic events, according to Thai Geological Survey amplification factors.

High-rise buildings in Bangkok typically use RC moment-resisting frames with flat-plate or flat-slab systems. While these are optimized for gravity loads, they are less effective against lateral seismic forces unless supplemented with shear walls or braced frames.

The collapse of a 33-story tower under construction during the March 28, 2025, earthquake exemplifies a critical vulnerability: incomplete lateral bracing during the construction phase. At this stage, vertical loads are often supported by temporary shoring, but full diaphragm action (e.g., continuity of floor slabs) and completed lateral systems (e.g., core walls) are usually not yet in place. This significantly reduces both structural stiffness and damping capacity.

USGS ShakeMap data for the 2025 event reported a PGA of 0.05–0.07 g in Bangkok (Modified Mercalli Intensity VI), amplified by soft-soil resonance to 0.1–0.15 g. Peak ground velocity (PGV) ranged from 5–7 cm/s—sufficient to excite the natural frequency of a 33-story building, estimated to be between 0.2–0.5 Hz. The resulting excessive sway likely caused punching shear failure at flat-slab column connections or buckling of unbraced perimeter columns.

Structures built before 2009, under the older DPT 1301-48 standard with no seismic provisions, fared worse, with widespread reports of cracked facades across the city.

The collapse underscores a gap in Thai seismic design standards. While DPT 1302-52 accounts for local events (e.g., the Mae Lao Fault, approximately 50 km away), it underestimates the long-period surface wave effects from distant large-magnitude earthquakes like the 2025 Mw 7.7 event. This leaves construction-phase high-rises—of which Bangkok has over 1,000—particularly vulnerable.

4.3 Updated Casualty and Damage Reports

Recent probabilistic seismic hazard assessments for Myanmar have highlighted the significant seismic risks associated with the Sagaing Fault, especially near major urban centers like Mandalay. A study by Yang et al. (2023) emphasizes the heightened seismic hazard levels near faults with high slip rates, including the Sagaing Fault and along Myanmar's western coast. The assessment indicates that areas in proximity to these faults are particularly susceptible to strong ground motions, necessitating rigorous seismic design considerations in these regions.

The enforcement of seismic building codes in Myanmar has been inconsistent, contributing to the vulnerability of structures during seismic events. The Myanmar National Building Code (MNBC) 2020 includes provisions for seismic design; however, the implementation of these standards varies across regions. A study by Linn (2013) underscores that many reinforced concrete buildings in Myanmar have been constructed without adherence to national building codes or seismic design considerations, highlighting the urgent need for standardized enforcement to mitigate earthquake risks.

• Myanmar: As of 8:30 PM PDT March 29, 2025, Myanmar’s military junta reports 1644 deaths and over 3,000 injuries (Reuters 2025). USGS models estimate a potential toll exceeding 10,000-100,000, awaiting confirmation (USGS 2025).

• Thailand: Bangkok reports 10 deaths and dozens trapped in the skyscraper collapse, with 50+ injuries citywide (CNN 2025).

• Mandalay: Multi-story URM and RC collapses align with MMI VIII-IX and PGV > 100 cm/s (USGS 2025).

• Nay Pyi Taw: Liquefaction and road buckling reported, consistent with MMI VI-VII.

• Bangkok: The 33-story tower collapse killed at least 10, driven by reported MMI V and amplified PGA (0.1-0.2%g), higher than predicted.

4.4 Long-Distance Collapse in Bangkok (965 km Away)

The building, intended to house Thailand’s State Audit Office, was being constructed by a joint venture between Italian-Thai Development (ITD), a prominent Thai developer, and China Railway No. 10 Engineering Group, a state-owned Chinese firm. Prior to the collapse, the Anti-Corruption Organisation of Thailand had flagged concerns about construction delays, worker shortages, and irregularities. Preliminary investigations cited substandard steel and unsafe construction practices as likely causes contributing to the catastrophic failure (Reuters 2025c).

The skyscraper collapse was influenced by:

• Low-Frequency Energy: PGV of 1-2 cm/s in Bangkok caused long-period resonance in tall structures (USGS 2025).

• Site Amplification: The Chao Phraya Basin amplified PGA to 0.1-0.2%g, exceeding predictions (0.01-0.1%g) as shown in the Prediction and Observations chart (USGS 2025).

• Construction Phase Vulnerability: The tower lacked full shear walls, with temporary supports inadequate for dynamic loads.

• Geologic Pathway: Efficient wave propagation sustained MMI V-VI, as per the intensity map.

• Substandard Materials: Early testing revealed some samples of substandard steel. More testing is required.

5. Structural Engineering Implications and Post-Earthquake Monitoring

To enhance Myanmar's resilience to seismic events, it is imperative to implement comprehensive mitigation strategies.These should include the development and enforcement of robust seismic building codes, public education on earthquake preparedness, and the establishment of early warning systems. The Global Earthquake Model (GEM) Foundation's seismic risk profile for Myanmar provides valuable insights into the country's seismic vulnerabilities and can serve as a foundational resource for policymakers and engineers in formulating effective mitigation plans.​

5.1 Ground Motion and Design Spectra

The USGS maps and Prediction and Observations chart indicate that PGA and PGV may have exceeded design levels, necessitating updated hazard maps with region-specific GMPEs, far-field effects, and soil amplification factors (Boore et al. 2014; USGS 2025).

5.2 Retrofitting Existing Structures

• URM: Steel/RC jacketing, wall anchorage.

• RC Frames: Shear walls, ductile retrofits (e.g., FRP wrapping).

• Foundations: Deep piles or soil stabilization for liquefaction-prone areas.

5.3 New Construction Recommendations

• Performance-based design for 475- and 2,475-year events.

• Ductile RC detailing (ACI 318-19).

• Base isolation/damping for high-rises on soft soils.

5.4 Bangkok Collapse Lessons

• Mandate robust temporary bracing during construction.

• Conduct geotechnical analysis for basin effects, especially given the underprediction of far-field PGA (USGS 2025).

• Install real-time seismic monitoring.

5.5 Post-Earthquake Monitoring

Crack monitors (e.g. Buildera CRACKMON® or similar) can enhance post-quake assessment (Buildera 2025):

• Application: Attach CRACKMON 4020A or 5020AV models to damaged structures to measure crack width changes (±0.1 mm resolution).

• Pre-Aftershock Use: Deploy pre-aftershock to establish baseline crack propagation rates, identifying potential collapse risks.

• Post-Quake Assessment: Monitor residual capacity, guiding evacuation or retrofitting.

• Advantages: Non-invasive, cost-effective, and reusable.

6. CONCLUSIONS AND RECOMMENDATIONS

The March 28, 2025, magnitude 7.7 earthquake in central Myanmar delivered widespread devastation across the epicentral region and produced unexpected structural failures over 1,000 kilometers away in Bangkok, Thailand. With more than 1,600 confirmed fatalities, thousands injured, and substantial infrastructure loss, the quake stands as one of the most impactful seismic events in Southeast Asia in recent decades.

This earthquake reaffirmed several key lessons about regional seismic hazards and revealed new vulnerabilities that merit further attention:

6.1 Key Conclusions

1. High Seismic Risk Along the Sagaing Fault:

   • The earthquake reaffirms that the Sagaing Fault remains highly active, with the potential for large, shallow earthquakes along segments that pass directly beneath densely populated areas like Mandalay and Nay Pyi Taw.

   • Strain accumulation rates suggest that other segments may also be nearing rupture in the coming decades.

2. Widespread Structural Vulnerability in Myanmar:

   • A large portion of Myanmar’s building stock remains highly susceptible to collapse due to non-engineered construction, especially unreinforced masonry (URM) and non-ductile concrete frames.

   • Even modest seismic forces can cause catastrophic outcomes in such buildings, as seen in rural areas and schools like the one that collapsed in Kyaukse. Expected aftershocks exceeding magnitude 6 will likely cause incremental damage to impaired structures.

3. Unexpected Damage in Distant Regions:

   • The collapse of a 33-story high-rise in Bangkok—over 965 km from the epicenter—challenges assumptions about how far damaging seismic waves can travel.

   • Long-period ground motions, amplified by Bangkok’s soft clay basin, likely contributed to the failure, despite low peak ground acceleration (PGA) levels.

4. Limitations of Conventional Seismic Models:

   • Ground motion prediction tools (e.g., USGS ShakeMap) effectively captured regional PGA patterns, but failed to predict the amplitude and duration of long-period waves in distant basin environments.

   • This reinforces the need for improved modeling of spectral response, especially in urban areas with tall buildings.

5. Underdeveloped Monitoring and Emergency Infrastructure:

   • Myanmar’s limited network of seismic monitoring stations and delayed emergency response capacity hindered both real-time data collection and post-event rescue efforts.

   • Public communication infrastructure, particularly mobile networks and internet services, were overwhelmed or disabled in the immediate aftermath.

6.2 Recommendations

1. Seismic Code Enforcement and Retrofitting:

   • Myanmar must accelerate efforts to adopt and enforce modern seismic building codes nationwide.

   • Priority should be given to schools, hospitals, and emergency shelters. Incentivized retrofitting programs should target vulnerable low-rise buildings and URM structures.

2. Site-Specific Risk Assessment in Bangkok and Similar Cities:

   • Bangkok and other cities built on soft clay or sedimentary basins must reassess the seismic performance of high-rise structures under long-period motion.

   • Building codes should incorporate spectral design parameters tailored to site amplification and resonance effects.

3. Post-Earthquake Structural Monitoring:

   • Aftershocks remain a serious concern. Authorities in both Myanmar and Thailand should implement rapid structural screening programs for buildings showing signs of cracking, displacement, or foundation settlement.

   • Key high-rise structures in Bangkok should be instrumented with accelerometers, tilt sensors, and structural crack monitors to assess real-time performance during future events.

4. Enhanced Seismic Instrumentation:

   • Regional seismic monitoring should be expanded with a denser network of digital strong-motion stations, particularly near known fault segments and major cities.

   • Data from these stations should feed into open-access platforms to improve regional and global hazard modeling.

5. Public Education and Preparedness:

   • Earthquake preparedness programs—including evacuation drills, emergency supply kits, and public training on how to respond during shaking—should be instituted at the national level.

   • In areas with limited emergency services, community-based response teams should be equipped and trained in first response and search and rescue.

The 2025 Myanmar earthquake offers a sobering reminder of the region’s seismic potential and the complex dynamics of earthquake-induced damage across different geologies and building types. Proactive engineering, planning, and policy decisions made in the coming years will determine whether future events result in fewer casualties—or repeat the devastating outcomes witnessed this March.

References (ASCE FORMAT)

1. American Concrete Institute (ACI). (2019). Building code requirements for structural concrete (ACI 318-19) and commentary. ACI, Farmington Hills, MI.

2. Boore, D. M., Stewart, J. P., Seyhan, E., and Atkinson, G. M. (2014). “NGA-West2 equations for predicting PGA, PGV, and 5% damped PSA for shallow crustal earthquakes.” Earthquake Spectra, 30(3), 1057–1085. https://doi.org/10.1193/070113EQS184M

3. Buildera. (2025). CRACKMON 224 and 4020 crack monitors: Technical specifications. Buildera. Accessed March 28, 2025. https://www.buildera.com/crackmon

4. Chiewanichakorn, M. (2024). Seismic design of high-rise building using performance based design (PBD). Meinhardt – Transforming Cities, Shaping the Future. Accessed March 30, 2025. https://www.meinhardt.net/news/seismic-design-of-high-rise-building-using-performance-based-design-pbd/

5. CNN. (2025). “Myanmar earthquake: At least 10 dead in Bangkok skyscraper collapse.” CNN, March 28, 2025. Accessed March 28, 2025. https://www.cnn.com/2025/03/28/asia/myanmar-earthquake-bangkok-collapse

6. El País. (2025). “El terremoto en Myanmar deja miles de víctimas (y la junta militar pide ayuda a la comunidad internacional).” El País, March 30, 2025. Accessed March 30, 2025. https://elpais.com/expres/2025-03-30/el-terremoto-en-myanmar-deja-miles-de-victimas-y-la-junta-militar-pide-ayuda-a-la-comunidad-internacional.html

7. Kongkunakornkul, P. (2025). "Fear, Chaos as Rare Quake Grinds Thailand's Capital to a Halt." Reuters. Accessed April 1, 2025. https://www.reuters.com/world/asia-pacific/after-quake-thailands-capital-grinds-halt-amid-fear-chaos-2025-03-28/

8. Lowitz, G. (2014). Earthquake! How crack monitors save lives and structures in seismic zones. Buildera. Accessed March 30, 2025. https://www.buildera.com/earthquake-how-crack-monitors-save-lives-structures-white-paper​

9. Myanmar National Building Code (MNBC). (2016). Myanmar National Building Code: Seismic design provisions.Ministry of Construction, Nay Pyi Taw, Myanmar.

10. New York Post. (2025a). “Thousands feared dead after powerful earthquake rocks Thailand and Myanmar – toppling buildings and leaving behind hundreds of miles of destruction.” New York Post, March 28, 2025. Accessed March 30, 2025. https://nypost.com/2025/03/28/world-news/earthquake-rocks-thailand-and-myanmar-triggering-collapse-of-bangkok-high-rise/

11. New York Post. (2025b). “Miracle baby born on Bangkok street as deadly earthquake rattled hospital, killed thousands.” New York Post, March 29, 2025. Accessed March 30, 2025. https://nypost.com/2025/03/29/world-news/mother-gives-birth-on-bangkok-street-amid-myanmar-earthquake/

12. NPR. (2025). “‘Am I going to survive?’ Myanmar's earthquake death toll jumps to more than 1,600.” NPR, March 29, 2025. Accessed March 30, 2025. https://www.npr.org/2025/03/29/g-s1-57121/myanmar-earthquake-death-toll-jumps.

13. Ornthammarath, T., Jirasakjamroonsri, A., Pornsopin, P., Rupakhety, R., Poovarodom, N., Warnitchai, P., and Toe, T. T. (2023). “Preliminary analysis of amplified ground motion in Bangkok basin using HVSR curves from recent moderate to large earthquakes.” Geoenvironmental Disasters, 10(28). https://doi.org/10.1186/s40677-023-00259-0

14. Pietrobelli, M., and Timpani, A. (2016). “Structural crack monitoring.” Buildera Application Note AN-16005. Accessed March 30, 2025. https://www.buildera.com/structural-crack-monitoring-application-note-an-16005

15. Reuters. (2025a). “Myanmar earthquake kills at least 694, injures hundreds.” Reuters, March 28, 2025. Accessed March 28, 2025. https://www.reuters.com/world/asia-pacific/myanmar-earthquake-2025-03-28

16. Reuters. (2025b). “Powerful earthquake kills more than 140 in Myanmar, death toll likely to rise.” Reuters, March 28, 2025. Accessed March 30, 2025. https://www.reuters.com/world/asia-pacific/strong-earthquake-central-myanmar-panic-bangkok-2025-03-28/

17. Reuters. (2025c). “Thai watchdog had flagged concerns over building that collapsed in earthquake.” Reuters, March 31, 2025. Accessed March 31, 2025. https://www.reuters.com/world/asia-pacific/thai-watchdog-had-flagged-concerns-building-that-collapsed-earthquake-2025-03-31/

18. Thailand Business News. (2025). "Chinese Construction Firm Under Investigation Following Bangkok Building Collapse." Thailand Business News, March 28, 2025. https://www.thailand-business-news.com/real-estate/206749-chinese-contruction-firm-under-investigation-following-bangkok-building-collapse

19. The Australian. (2025). “Myanmar junta dropped bombs on civilians fleeing quake: UN.” The Australian, March 30, 2025. Accessed March 30, 2025. https://www.theaustralian.com.au/world/myanmar-junta-continues-to-bomb-resitance-strongeholds/news-story/b407c1ec3237e9b12e78e2a86703c5ea

20. The Guardian. (2025). “Myanmar earthquake: Level of devastation 'hasn't been seen in over a century in Asia', says Red Cross – as it happened.” The Guardian, March 30, 2025. Accessed March 30, 2025. https://www.theguardian.com/world/live/2025/mar/30/myanmar-earthquake-search-for-survivors-un-warning-medical-supplies-shortage-news-updates

21. The Nation Thailand. (2025). "Chatuchak building collapse due to unstable structure: Bangkok dept." The Nation Thailand, March 28, 2025. https://www.nationthailand.com/news/general/40048009

22. The Times. (2025). “‘How could I have survived? I couldn't save my friend who was inside’.” The Times, March 30, 2025. Accessed March 30, 2025. https://www.thetimes.co.uk/article/how-could-i-have-survived-i-couldnt-save-my-friend-who-was-inside-zft9kf630

23. U.S. Geological Survey (USGS). (2025a). M 7.7 – 2025 Myanmar, Burma (Myanmar) earthquake. U.S. Geological Survey. Accessed March 30, 2025. https://earthquake.usgs.gov/earthquakes/eventpage/us7000pn9s

24. U.S. Geological Survey (USGS). (2025b). “M 7.7 – 17.2 km NW of Sagaing, Myanmar: Earthquake summary, ShakeMap, and prediction and observations data.” USGS Earthquake Hazards Program, Version 8. Accessed March 28, 2025. https://earthquake.usgs.gov/earthquakes/eventpage/us7000pn9s

25. Wells, D. L., and Coppersmith, K. J. (1994). “New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement.” Bulletin of the Seismological Society of America, 84(4), 974–1002.

26. Wikipedia. (2025). “2025 Myanmar earthquake.” Wikipedia, March 30, 2025. Accessed March 30, 2025. https://en.wikipedia.org/wiki/2025_Myanmar_earthquake

27. Worden, C. B., Gerstenberger, M. C., Rhoades, D. A., and Wald, D. J. (2012). “Probabilistic relationships between ground-motion parameters and Modified Mercalli Intensity in California.” Bulletin of the Seismological Society of America, 102(1), 204–221. https://doi.org/10.1785/0120110156

Note: Casualty figures reflect the latest reports as of 8:30 PM PDT, March 29, 2025. The USGS 10,000+ estimate is a probabilistic projection, not yet verified.