Dr. Ing. Jorge E. Alva Hurtado

Mag. Ing. Carmen Ortiz Salas

Dr. José Macharé O.

Ing. Jorge Soto Huamán

www.jorgealvahurtado.com

www.red-acelerografica-peru.com

THE EFFECTS OF THE 26/05/19 LAGUNAS EARTHQUAKE ON THE PERUVIAN JUNGLE

Tectonic setting

Peak GroundAcceleration (m/s2)

Peru seismicity

MAXIMUM SEISMIC INTENSITIES (Alva et.al, 1984)

Seismic hazardMAX PGA 10% EXC, 10-YEARS (Gamarra, 2009)

The Lagunas earthquake 26/05/2019

Data Source

Geographical

Depth (Km)Hora

EpicentralUTC

coordinates (°)

Latitude Longitude

South West

IGP -5.740 -75.550 135.0 07:41:12

USGS -5.796 -75.298 109.9 07:41:14

The Lagunas earthquake: tectonic process

Accelerometric data:

gathering and analysis

- Recording in 60 stations

- Several institutional networks

- Accurate análisis

LEGEND

Station

Station

Station

Station

Epicenter

Epicenter

ACELEROGRAMA ESTACIÓN SENCICO-CISMID IQUITOS

GROUND MOTION RECORD, V COMPONENT

SEISMIC STATION UNTRM

SEISMIC STATIONCIP CIP MOYOBAMBASEISMIC STATION SENCICO – CIISMID IQUITOS

SEISMIC STATION CIP TARAPOTO

SEISMIC STATION UNJ

SEISMIC STATIION CIP AMAZONZAS

LEGEND

Station CIP UNI

Epicenter USGS

Epicenter IGP

Station SENCICO - CISMID

Time (sec)

Acc

ele

rati

on

(cm

/s2)

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

ACELEROGRAMA ESTACIÓN SENCICO-CISMID IQUITOS

GROUND MOTION RECORD, NS COMPONENT

SEISMIC STATION UNTRM

SEISMIC STATIONCIP CIP MOYOBAMBASEISMIC STATION SENCICO – CIISMID IQUITOS

SEISMIC STATION CIP TARAPOTO

SEISMIC STATION UNJ

SEISMIC STATIION CIP AMAZONZAS

LEGEND

Station CIP UNI

Epicenter USGS

Epicenter IGP

Station SENCICO - CISMID

Time (sec)

Acc

ele

rati

on

(cm

/s2)

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

Acc

ele

rati

on

(cm

/s2)

Time (sec)

Acc

ele

rati

on

(cm

/s2)

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

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ele

rati

on

(cm

/s2)

Time (sec)

Acc

ele

rati

on

(cm

/s2)

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

GROUND MOTION RECORD, EWCOMPONENT

ACELEROGRAMA ESTACIÓN SENCICO-CISMID IQUITOS

SEISMIC STATION UNTRM

SEISMIC STATIONCIP CIP MOYOBAMBASEISMIC STATION SENCICO – CIISMID IQUITOS

SEISMIC STATION CIP TARAPOTO

SEISMIC STATION UNJ

SEISMIC STATIION CIP AMAZONZAS

LEGEND

Station CIP UNI

Epicenter USGS

Epicenter IGP

Station SENCICO - CISMID

Time (sec)

Acc

ele

rati

on

(cm

/s2)

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Time (sec)

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ele

rati

on

(cm

/s2)

Time (sec)

Acc

ele

rati

on

(cm

/s2)

Time (sec)

Acc

ele

rati

on

(cm

/s2 )

Maximum Peak Ground

Accelerations recorded

LEGEND

Station

Station

Station

Station

Epicenter

Epicenter

PEAK GROUND ACCELERATIONS OF MOTION RECORD IN PERU,

ACCELEROGRAPHIC NETWORK: CIP AND UNI

N° INSTITUTION STATION LOCATIONEPICENTRAL

DISTANCE (KM)

TYPE OF SOILPEAK VALUE, WITH CORRECTION (cm/seg²) MAXIMUN PEAK

VALUE(cm/seg²)

MAXIMUN PEAK VALUE

(g)PGA EO PGA NS PGA V

1POSGRADO FIC UNI / UNTRM

UNTRMAMAZONAS,

CHACHAPOYAS, CHACHAPOYAS

292HIGH

COMPRESSIBILTY CLAY

95.84 87.45 53.49 95.84 0.096

2 CIPCIP

MOYOBAMBA

SAN MARTIN, MOYOBAMBA, MOYOBAMBA

192 CLAY 91.29 78.76 90.16 91.29 0.093

3 CIP CIP TARAPOTOSAN MARTIN, SAN

MARTIN, TARAPOTO153

HIGH COMPRESSIBILTY

CLAY58.18 79.56 67.86 79.56 0.081

4 CIP CIP AMAZONASAMAZONAS,

CHACHAPOYAS, CHACHAPOYAS

294HIGH

COMPRESSIBILTY CLAY

78.91 53.98 53.05 78.91 0.08

5POSGRADO FIC

UNIPACASMAYO

LA LIBERTAD, PACASMAYO, PACASMYO

529 GRAVEL SANDY 38.07 25.02 17.99 38.07 0.039

6POSGRADO FIC

UNIUNJ CAJAMARCA, JAEN, JAEN 391

POORLY GRADED GRAVEL

29.24 32.60 19.23 32.60 0.033

7POSGRADO FIC

UNIUNC

CAJAMARCA, CAJAMARCA, CAJAMARCA

391 CLAYEY SILT 25.26 22.63 17.09 25.26 0.025

8 CIP CIP LA LIBERTADLA LIBERTAD, TRUJILLO,

TRUJILLO494 SAND WITH GRAVEL 20.60 19.93 17.43 20.60 0.021

9 CIP CIP CAJAMARCACAJAMARCA,

CAJAMARCA, CAJAMARCA393 CLAYEY GRAVEL 17.27 17.63 9.44 17.63 0.018

10 CIP / UPAO UPAOLA LIBERTAD, TRUJILLO,

TRUJILLO495 CLAYEY SAND 16.71 17.62 13.63 17.62 0.018

11 CIP CIP PIURA PIURA, PIURA, PIURA 596 CLAYEY SAND 17.23 15.54 10.68 17.23 0.017

12 CIP CIP TUMBESTUMBES, TUMBES,

TUMBES619

LOW COMPRESSIBILTY

CLAY14.59 11.48 5.93 14.59 0.015

13 CIPCIP

LAMBAYEQUELAMBAYEQUE, CHICLAYO,

PIMENTEL528 CLAY WITH SILT 13.17 13.41 13.61 13.41 0.013

Methodological summary and results

• This earthquake was registered in more than 60 accelerographic stations in Peru

and Ecuador.

• The maximum acceleration recorded in Peru was at the UNTRM Station in

Chachapoyas, an EO component of 95.84 cm/sec². The maximum acceleration

recorded in Ecuador was at the Barrio Centenario Station in Guayaquil, EO

component of 36.70 cm/sec².

• The records were corrected by baseline and filtered (band-pass from 0.1 hertz to

25 hertz) before proceeding to identify the maximum acceleration peaks, with the

use of SIPA v. 2017.

Effects on society and nature: Losses and damages

• 2 people dead, and 32 injured (17 in Peru, 15 in

Ecuador).

• 1,633 affected houses, 716 of which declared

inhabitable.

• 296 schools affected, 7 inhabitable.

• 40 health centers, 6 inhabitable.

• 15 religious buildings, 5 collapsed.

• 21 commercial buildings.

• 54 km of affected highway roads.

• 5 pedestrian bridges affected, 1 collapsed.

National Emergency Operations Center (COEN), 30 May 2019 .

Yurimaguas (Province of Alto Amazonas, Loreto)

60 km from the epicenter.

Santa Cruz Church (Province of Alto Amazonas, Loreto). 40 km.

Progreso School (Distrito de Santa Cruz, Province of Alto Amazonas, Loreto)

Huatapi Health Centre (Distrito de Santa Cruz, province of Alto Amazonas, Loreto)

Cajamarca – Cajabamba

Highway (340 km from the

epicenter)

Tarapoto – Yurimaguas

Highway (80 km from the

epicenter)

Affected highways

Seis de Enero Town centre

(Distrito de Santa Cruz, Alto

Amazonas, Loreto)

Ground effects

Seis de Enero Town centre (Santa Cruz, Alto Amazonas, Loreto)“El Sauce” Resort (San Martín)

Malecón del río Huallaga (District of Lagunas,

Province of Alto Amazonas, Loreto)

Centro Poblado Tamarate, near the district

of Lagunas (Rengifo, 2019).

MAP OF MAXIMUM CREDIBLE EARTHQUAKE ( 500 year of return period)

S2

NORMALIZED RESPONSE SPECTRA FROM DATA MAY 26, LAGUNAS EARTHQUAKE

Period (s)

Seis

mic

Am

plif

icat

ion

From PERUVIAN CODE E.030 (2018)

Site coefficient “S”

Short Period (Tp) and Long Period (TL)

GEOPHYSICAL TESTS CARRIED OUT (MICROTREMORES, MASW, MAM Y RESISTIVIDAD ELECTRICA) IN

JAEN, CHACHAPOYAS, MOYOBAMBA AND TARAPOTO

SEISMIC STATION UNTRM

Time (s)

PSEUDO ACCELERATION RESPONSE SPECTRUM – UNTRM STATION

M8.0 Lagunas, Peru Earthquake. May 26, 2019

FOURIER AMPLITUDE SPECTRUM – UNTRM STATION

M8.0 Lagunas, Peru Earthquake. May 26, 2019

Acc

ele

rati

on

(cm

/s2)

Acc

ele

rati

on

(cm

/s2)

Acc

ele

rati

on

(cm

/s2)

Time ( sec)

Time ( sec)

Time ( sec)

Period ( s )

Pse

ud

o-A

cce

lera

tio

n(c

m/s

2)

Am

plit

ud

e(c

m/s

2-s

)

Frequency (Hz)

Vs30 = 241 m/s SUELO TIPO DS2

UNTRM STATION

0.0

3.0

6.0

9.0

12.0

15.0

18.0

21.0

24.0

27.0

30.0

0 100 200 300 400 500 600 700

Pro

fun

did

ad [m

]Vs [m/s]

1

2

3

SPECTRAL RATIO H/V– ACCELEROGRAPH

Period ( s )

Am

plit

ud

e(H

/V)

Period ( s )A

mp

litu

de

(H/V

)

SPECTRAL RATIO H/V– MICROTREMOR

DEP

TH (

m)

S-WAVE VELOCITY PROFILE

FROM : MASW RESULTS

UNTRM STATION

20.0

18.0

16.0

14.0

12.0

10.0

8.0

6.0

4.0

2.0

-0.0

-2.0

Depth

(m

)

0.0 4.0 8.0 12.0 16.0 20.0 24.0 28.0 32.0 36.0 40.0 44.0 48.0

Distance (m)

Vs- UNTRM

(m/sec)

Vs

150

200

250

300

Scale = 1/200

0

10

20

30

40

50

60

70

80

90

100

0 200 400 600 800 1000

Pro

fundid

ad [

m]

Vs [m/s]

1

2

3

Estrato Vs(m/s)

1 <150

2 150-200

3 200-250

4 250-300

Caracterización geotécnica

Material de consistencia muy blanda

Material de consistencia blanda

Material de consistencia media

Material de consistencia dura

20.0

18.0

16.0

14.0

12.0

10.0

8.0

6.0

4.0

2.0

-0.0

-2.0

Depth

(m

)

0.0 4.0 8.0 12.0 16.0 20.0 24.0 28.0 32.0 36.0 40.0 44.0 48.0

Distance (m)

Vs- UNTRM

(m/sec)

Vs

150

200

250

300

Scale = 1/200

Vs100 = 370 m/s

DEP

TH (

m)

FROM : MASW AND MAM RESULTS

FROM : MASW-2D RESULTS

S-WAVE VELOCITY PROFILE

CIP TARAPOTO STATION

20.0

18.0

16.0

14.0

12.0

10.0

8.0

6.0

4.0

2.0

-0.0

Depth

(m

)

0.0 4.0 8.0 12.0 16.0 20.0 24.0 28.0 32.0 36.0 40.0 44.0 48.0

Distance (m)

Vs-CIP TARAPOTO

(km/sec)

Vs

0.20

0.25

0.30

0.35

0.40

0.45

Scale = 1/250

Estrato Vs(m/s)

1 200-250

2 250-300

3 300-350

4 350-400

Material de consistencia dura

Material de consistencia rígida

Caracterización geotécnica

Material de consistencia blanda

Material de consistencia media a dura

Vs80 = 381 m/s

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

0 100 200 300 400 500 600

Pro

fundid

ad [

m]

Vs [m/s]

2

1

3

4

FROM : MASW AND MAM RESULTS

FROM : MASW-2D RESULTS

S-WAVE VELOCITY PROFILE

DEP

TH (

m)

• In Peru, the periods of the study area were determined by two different methods:

spectral quotient of the microtremors records, spectral quotient of the time-history

records of acceleration, concluding that the values of soil periods increase with

earthquakes of greater magnitude with respect to the values obtained by

microtremors measurements due to the effect of the non-linearity of the soil.

• The shear-wave velocity profiles (Vs) were determined in the accelerographic

booths of Peru, at different depths those that classified according to Standard E-

030 as intermediate soil (S2) and according to ASCE-7 Type D and C soils.

Methodological summary and results

• The Andean Amazonian belt: area of intermediate-depth high-magnitude earthquakes.

They have large perception areas.

• The strength is attenuated by focal depth (100 – 150 km) and the thick sedimentary

pack they traverse. Moderate intensities (< V MM) were expected. Nonetheless, some

areas may be strongly affected. Process of disaster risk management is a priority.

• Intense damage and losses are related to regional to:

a) Flat to gently inclined river terraces, subjected to periodic fluvial and pluvial floods.

b) Bad quality foundation soils: developed on transported loose sand-silt-clay mixes

with shallow groundwater table.

c) Precarious settlement without guidelines for risk management,

d) Absence of actions for risk reduction and preparedness face to natural hazards.

Recommendation: General and thorough assessment of risk, planning safe land

occupation, actions for risk reduction, and capacity strengthening to local authorities for a

safer, healthier and sustainable development.

Conclusive remarks and recommendation for DRM