Deformation demands from the October 30th earthquake are significantly higher than those from the August 24th earthquake It does not matter whether the October 30th earthquake is called the mainshock or aftershock What matters is that a structure experiences all events (foreshocks, mainshock and aftershocks) Dependent events (foreshocks and aftershocks) are usually ignored in seismic hazard analysis In seismic design, amplitudes and load cycles from all dependent events should be considered

1. Ground Motions in Norcia, Italy
M 6.6 Earthquake on October 30, 2016
M 6.2 Earthquake on August 24, 2016
Praveen K. Malhotra
October 31, 2016

2. 2 of 20
Accelerations in Norcia M 6.6 @ 5.4 km
October 30, 2016

3. 3 of 20
Accelerations in Norcia M 6.2 @ 14 km
August 24, 2016

4. 4 of 20
Resultant Horizontal Accelerations in Norcia
M 6.6 @ 5.4 km October 30, 2016
PGA = 0.526 g

5. 5 of 20
Resultant Horizontal Accelerations in Norcia
M 6.2 @ 14 km August 24, 2016
PGA = 0.452 g

6. 6 of 20
Velocities in Norcia M 6.6 @ 5.4 km
October 30, 2016

7. 7 of 20
Velocities in Norcia M 6.2 @ 14 km
August 24, 2016

8. 8 of 20
Resultant Horizontal Velocities in Norcia
M 6.6 @ 5.4 km October 30, 2016
PGV = 53 cm/s

9. 9 of 20
Resultant Horizontal Velocities in Norcia
M 6.2 @ 14 km August 24, 2016
PGV = 30.2 cm/s

10. 10 of 20
Displacements in Norcia M 6.6 @ 5.4 km
October 30, 2016

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Displacements in Norcia M 6.2 @ 14 km
August 24, 2016

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Resultant Horizontal Displacements in
Norcia M 6.6 @ 5.4 km October 30, 2016
PGD = 24.9 cm

13. 13 of 20
Resultant Horizontal Displacements in
Norcia M 6.2 @ 14 km August 24, 2016
PGD = 8.19 cm

14. 14 of 20
Tripartite Response Spectrum of Horizontal Ground
Motion in Norcia M 6.6 @ 5.4 km October 30, 2016

15. 15 of 20
Tripartite Response Spectrum of Horizontal Ground
Motion in Norcia M 6.2 @ 14 km August 24, 2016

16. 16 of 20
Acceleration-Deformation Response Spectrum of Horizontal
Ground Motion in Norcia M 6.6 @ 5.4 km October 30, 2016

17. 17 of 20
Acceleration-Deformation Response Spectrum of Horizontal
Ground Motion in Norcia M 6.2 @ 14 km August 24, 2016

18. 18 of 20
Deformation Demands on Structures of Various
Lateral Strengths in Norcia
Lateral
Strength
(% of Weight)
Deformation Demands
M 6.2 August 24 M 6.6 October 30
50% 1.9 cm 27 cm
30% 6.8 cm 24 cm
25% 6.7 cm 21 cm
20% 17 cm 26 cm
10% 17 cm 26 cm

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Comments on Norcia Ground Motions
• Deformation demands from the October 30th
earthquake are significantly higher than those from
the August 24th earthquake
• It does not matter whether the October 30th
earthquake is called the mainshock or aftershock
• What matters is that a structure experiences all
events (foreshocks, mainshock and aftershocks)
• Dependent events (foreshocks and aftershocks)
are usually ignored in seismic hazard analysis
• In seismic design, amplitudes and load cycles from
all dependent events should be considered

20. 20 of 20
Acknowledgment
• Data may be obtained from Italian National
Strong Motion Network (RAN) managed by
the Department of Civil Protection (DPC):
http://ran.protezionecivile.it/IT/index.php
• Data processing is preliminary
• No warranty of any kind is assumed