Zürcher Nachrichten - Scientists explain why Myanmar quake was so deadly

EUR -
AED 3.961939
AFN 77.474194
ALL 99.247373
AMD 421.476505
ANG 1.931049
AOA 985.360016
ARS 1157.541382
AUD 1.725434
AWG 1.941611
AZN 1.814769
BAM 1.954646
BBD 2.179044
BDT 131.152551
BGN 1.952718
BHD 0.406543
BIF 3207.420805
BMD 1.078673
BND 1.449551
BOB 7.457907
BRL 6.16829
BSD 1.079178
BTN 92.463826
BWP 14.815144
BYN 3.531731
BYR 21141.991123
BZD 2.16775
CAD 1.552745
CDF 3095.791321
CHF 0.951794
CLF 0.026421
CLP 1013.99603
CNY 7.828688
CNH 7.855177
COP 4517.374726
CRC 539.788747
CUC 1.078673
CUP 28.584835
CVE 110.199924
CZK 24.953987
DJF 192.188089
DKK 7.461602
DOP 68.290622
DZD 144.633908
EGP 54.561544
ERN 16.180095
ETB 142.865321
FJD 2.519187
FKP 0.832703
GBP 0.836613
GEL 2.976858
GGP 0.832703
GHS 16.713666
GIP 0.832703
GMD 77.788917
GNF 9303.304779
GTQ 8.320772
GYD 225.657389
HKD 8.393268
HNL 27.530661
HRK 7.537986
HTG 140.888676
HUF 400.937162
IDR 17934.350957
ILS 3.997136
IMP 0.832703
INR 92.152911
IQD 1407.071653
IRR 45394.038821
ISK 142.253052
JEP 0.832703
JMD 168.858068
JOD 0.764778
JPY 160.922979
KES 139.449974
KGS 93.336533
KHR 4290.903202
KMF 490.41045
KPW 970.787435
KRW 1589.939265
KWD 0.332516
KYD 0.897047
KZT 542.99132
LAK 23224.975651
LBP 96407.800471
LKR 318.675341
LRD 215.1011
LSL 19.812861
LTL 3.185041
LVL 0.652478
LYD 5.182319
MAD 10.387486
MDL 19.392443
MGA 5008.930878
MKD 61.309974
MMK 2264.442962
MNT 3766.483178
MOP 8.642325
MRU 42.534017
MUR 49.24209
MVR 16.653976
MWK 1865.286324
MXN 22.134693
MYR 4.784141
MZN 68.912549
NAD 19.812861
NGN 1655.659483
NIO 39.567089
NOK 11.31741
NPR 147.513772
NZD 1.899875
OMR 0.415269
PAB 1.078673
PEN 3.946221
PGK 4.390988
PHP 61.755529
PKR 302.113423
PLN 4.170365
PYG 8572.769541
QAR 3.926631
RON 4.961678
RSD 116.833988
RUB 91.511638
RWF 1528.963553
SAR 4.045145
SBD 9.168623
SCR 15.442581
SDG 647.72845
SEK 10.814263
SGD 1.447432
SHP 0.847668
SLE 24.577576
SLL 22619.234986
SOS 616.071745
SRD 39.430657
STD 22326.353608
SVC 9.438475
SYP 14024.750296
SZL 19.812861
THB 36.588498
TJS 11.73894
TMT 3.77428
TND 3.353396
TOP 2.597933
TRY 40.914596
TTD 7.313619
TWD 35.827919
TZS 2857.638343
UAH 44.640457
UGX 3947.704322
USD 1.078673
UYU 45.483216
UZS 13894.195195
VES 74.650489
VND 27593.94493
VUV 132.936281
WST 3.050235
XAF 653.8806
XAG 0.03185
XAU 0.000344
XCD 2.920325
XDR 0.813713
XOF 653.8806
XPF 119.331742
YER 265.368414
ZAR 19.766963
ZMK 9709.356384
ZMW 30.375038
ZWL 347.332271
  • BCE

    -0.0150

    22.945

    -0.07%

  • JRI

    0.0370

    12.977

    +0.29%

  • SCS

    0.0650

    11.025

    +0.59%

  • CMSC

    0.0000

    22.4

    0%

  • RBGPF

    1.0000

    68

    +1.47%

  • BCC

    -0.2150

    97.875

    -0.22%

  • NGG

    -0.2200

    65.39

    -0.34%

  • GSK

    -0.4500

    38.29

    -1.18%

  • RIO

    0.0000

    60.08

    0%

  • RYCEF

    -0.0100

    9.69

    -0.1%

  • CMSD

    0.1010

    22.911

    +0.44%

  • BTI

    -0.1350

    41.235

    -0.33%

  • VOD

    -0.0450

    9.325

    -0.48%

  • RELX

    -0.1150

    50.295

    -0.23%

  • AZN

    -0.2950

    73.205

    -0.4%

  • BP

    -0.3900

    33.4

    -1.17%

Scientists explain why Myanmar quake was so deadly
Scientists explain why Myanmar quake was so deadly / Photo: Sai Aung MAIN - AFP

Scientists explain why Myanmar quake was so deadly

Experts say that the devastating earthquake in Myanmar on Friday was likely the strongest to hit the country in decades, with disaster modelling suggesting thousands could be dead.

Text size:

Automatic assessments from the United States Geological Survey (USGS) said the shallow 7.7-magnitude quake northwest of the central Myanmar city of Sagaing triggered a red alert for shaking-related fatalities and economic losses.

"High casualties and extensive damage are probable and the disaster is likely widespread," it said, locating the epicentre near the central Myanmar city of Mandalay, home to more than a million people.

Myanmar's ruling junta said on Saturday morning that the number killed had passed 1,000, with more than 2,000 injured.

However, the USGS analysis said there was a 35 percent chance that possible fatalities could be in the range of 10,000-100,000 people.

The USGS offered a similar likelihood that the financial damage could total tens of thousands of millions of dollars, warning that it might exceed the GDP of Myanmar.

Weak infrastructure will complicate relief efforts in the isolated, military-ruled state, where rescue services and the healthcare system have already been ravaged by four years of civil war sparked by a military coup in 2021.

- Dangerous fault -

Bill McGuire, emeritus professor of geophysical and climate hazards at University College London (UCL), said it was "probably the biggest earthquake on the Myanmar mainland in three-quarters of a century".

A 6.7-magnitude aftershock struck minutes after the first and McGuire warned that "more can be expected".

Rebecca Bell, a tectonics expert at Imperial College London (ICL), suggested it was a side-to-side "strike-slip" of the Sagaing Fault.

This is where the Indian tectonic plate, to the west, meets the Sunda plate that forms much of Southeast Asia -- a fault similar in scale and movement to the San Andreas Fault in California.

"The Sagaing fault is very long, 1,200 kilometres (745 miles), and very straight," Bell said. "The straight nature means earthquakes can rupture over large areas -- and the larger the area of the fault that slips, the larger the earthquake."

Earthquakes in such cases can be "particularly destructive", Bell added, explaining that since the quake takes place at a shallow depth, its seismic energy has dissipated little by the time it reaches populated areas above.

That causes "a lot of shaking at the surface", Bell said.

- Building boom -

Myanmar has been hit by powerful quakes in the past.

There have been more than 14 earthquakes with a magnitude of 6 or above in the past century, including a magnitude 6.8 earthquake near Mandalay in 1956, said Brian Baptie, a seismologist with the British Geological Survey.

Ian Watkinson, from the department of earth sciences at Royal Holloway University of London, said what had changed in recent decades was the "boom in high-rise buildings constructed from reinforced concrete".

Myanmar has been riven by years of conflict and there is a low level of building design enforcement.

"Critically, during all previous magnitude 7 or larger earthquakes along the Sagaing Fault, Myanmar was relatively undeveloped, with mostly low-rise timber-framed buildings and brick-built religious monuments," Watkinson said.

"Today's earthquake is the first test of modern Myanmar's infrastructure against a large, shallow-focus earthquake close to its major cities."

Baptie said that at least 2.8 million people in Myanmar were in hard-hit areas where most lived in buildings "constructed from timber and unreinforced brick masonry" that are vulnerable to earthquake shaking.

"The usual mantra is that 'earthquakes don't kill people; collapsing infrastructure does'," said Ilan Kelman, an expert in disaster reduction at UCL.

"Governments are responsible for planning regulations and building codes. This disaster exposes what governments of Burma/Myanmar failed to do long before the earthquake, which would have saved lives during the shaking."

- Skyscraper checks -

Strong tremors also rocked neighbouring Thailand, where a 30-storey skyscraper under construction was reduced to a pile of dusty concrete, trapping workers in the debris.

Christian Malaga-Chuquitaype, from ICL's civil and environmental engineering department, said the nature of the ground in Bangkok contributed to the impact on the city, despite being some 1,000 kilometres (620 miles) from the epicentre in Myanmar.

"Even though Bangkok is far from active faults, its soft soil amplifies the shaking," he said. "This affects especially tall buildings during distant earthquakes."

Malaga-Chuquitaype said the construction techniques in Bangkok favouring "flat slabs" -- where floors are held only by columns without using strengthening beams, like a table supported only by legs -- were a "problematic design".

He said that initial video analysis of the collapsed tower block in Bangkok suggested this type of construction technique had been used.

Roberto Gentile, a catastrophe risk modelling expert from UCL, said the "dramatic collapse" of the Bangkok tower block meant that "other tall buildings in the city may require a thorough assessment".

Bangkok city authorities said they will deploy more than 100 engineers to inspect buildings for safety after receiving more than 2,000 reports of damage.

P.E.Steiner--NZN