Logo link to homepage

Harrat Lunayyir

Photo of this volcano
  • Country
  • Volcanic Region
  • Landform | Volc Type
  • Last Known Eruption
  • 25.17°N
  • 37.75°E

  • 1,370 m
    4,495 ft

  • 231040
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number


Most Recent Bulletin Report: March 2011 (BGVN 36:03) Citation IconCite this Report

2009 seismic swarm, deformation, and 8 km surface rupture

An intense seismic swarm coupled with surface deformation spurred the evacuation of over 30,000 residents, led to an 8 km long surface rupture, and was consistent with the injection of a shallow dike that never reached the surface. Between April and June 2009 more than 30,000 earthquakes occurred beneath one of the lava fields of Saudi Arabia adjacent the N-central portion of the Red Sea and centered inland ~50 km ENE from the port city of Umm Lajj (figure 1). The field is known as Harrat Lunayyir (the words harrat and haarrat indicate a volcanic field, named and unnamed, respectively). Ultimately a narrow, 8 km long surface rupture developed and the seismicity declined. The event was interpreted as due to a shallow intrusion that did not reach the surface. Table 1 at the end of this report gives an overview of the crisis, which included evacuations.

Figure (see Caption) Figure 1. Index map (at upper right focused on the Red Sea) and the main map showing numerous named volcanic fields (harrats) in Saudi Arabia, including Lunayyir. The cities of Umm Lajj and Al Ays are discussed in text. Original map taken from SGS (2011).

This report is based on Pallister and others (2010) as well as a report from scientists from the USGS-USAID Volcano Disaster Assistance Program (VDAP) and the Saudi Geological Survey (SGS). The government of Saudi Arabia evacuated more than 30,000 people from the town of Al Ays on the SE margin of the volcanic field, due to fears that further larger earthquakes could occur or that there could be a volcanic eruption (figures 2 and 3). In response to this situation, SGS increased their presence in the region and installed a permanent telemetered seismic network of seven broadband seismometers in the area to better monitor the seismicity.

Figure (see Caption) Figure 2. The town of Al Ays is shown. About 30,000 people were evacuated from the area due to the earthquake swarm. Previous lava flows of the Harrat Lunayyir volcanic field cover much of the back and central portions of the photo beyond the town. Photograph courtesy of John Pallister (VDAP).
Figure (see Caption) Figure 3. Areal view of cinder cones found at Harrat Lunayyir. Photograph courtesy of John Pallister (VDAP).

A punctuated earthquake swarm began at Harrat Lunayyir in April 2009, with a peak on 19 May when 19 earthquakes of M 4 or greater occurred. The largest of those earthquakes was variably assessed as M 5.4 (SGS) and M 5.7 (USGS National Earthquake Information Center). It struck at 1735 UTC (2035 local time). The earthquake caused minor damage to structures in the town of Al Ays (40 km SE of the epicenter).

Surface rupture. In the northern central part of the lava field the initial surface rupture extended 3 km, trended NW, and appeared during the week preceding 19 May (when maximum earthquake magnitudes exceeded M 4). Associated with the M 5.4 earthquake on 19 May, the rupture lengthened to 8 km. The rupture had local vertical offsets of more than 1 meter and was several meters deep (figures 4 and 5). Event rates decreased dramatically on 20 May and maintained a relatively constant level, except for a few increases in event rate lasting 24 hours.

Figure (see Caption) Figure 4. The 8-km-long surface rupture that opened on 19 May 2009 seen here cutting across soft sediments in the Harrat Lunayyir region. Taken from SGS (2011).
Figure (see Caption) Figure 5. Wendy McCausland (USGS-VDAP seismologist) consults with Hani Zahran (Director of Earthquake and Volcanoes Center, Saudi Geological Survey) at the site of the 8 km long surface rupture that opened during the 19 May 2009 earthquake at Lunayyir. Photograph courtesy of John Pallister (VDAP).

Combining seismic with InSAR and modeling. Results from InSAR data and geodetic modeling were consistent with the timing of the seismic swarm. InSAR data showed that 75% of the deformation occurred during 8-27 May 2009, and 20% occurred during 27 May to 17 June (figure 6). Interferograms from May and June showed a broad area of deformation of about 2,000 km2, which is indicative of dyke intrusion. Envisat interferograms showed about 40 cm of uplift and over 1 m of E-W extension.

Figure (see Caption) Figure 6. For Lunayyir, plots of real-time seismic amplitude (RSAM) for 10-min intervals showing peak seismic energy releases for the vertical component of broadband seismic stations UMGS and LNYS (45 km WSE and 29 km SE from the epicenter of the M 5.4 earthquake on 19 May). The lower graph shows daily counts of very long frequency earthquakes recorded at both stations. InSAR-detected deformation periods are indicated by shading (yellow on colored versions). Taken from Pallister and others (2010).

Earthquakes suggestive of volcanism. Initially, scientists were unsure if the earthquakes were tectonic or volcanic in origin. On 12 June two members of a VDAP team deployed to Saudia Arabia at the request of the SGS to provide technical assistance. The VDAP and SGS teams determined that the earthquake pattern was that of a volcanic earthquake swarm. It was characterized by several ten's of thousands of small (under M 3) earthquakes during 24 April-31 July 2009, in a pattern of seismicity that waxed and waned. Earthquakes occurred of both varying magnitude and lacking tectonic mainshock-aftershock sequences. RSAM (real-time seismic-amplitude measurement) data showed that energy increased dramatically on 29 April, peaking on 19 May with the previously mentioned largest (M 5.4) event.

Other common volcanic-swarm characteristics included a high rate of occurrence of small compared to large events, and shallow event locations clustered beneath the lava field at around 5-10 km in depth. The event types included those of high-frequency (13-28 Hz), very low-frequency (less than 1 Hz), and high-frequency tremor. The latter contained embedded spasmodic bursts of high-frequency earthquakes (13-28 Hz).

An unusual aspect of the swarm was that both low- and very low-frequency earthquakes occurred, events that are usually associated with movements of fluids (magma, water or gas) and Strombolian explosions, but in this case both gas emissions and explosions were absent.

The VDAP and SGS teams concluded that there were three key lines of evidence that the earthquakes were volcanic. First, the earthquakes were occurring in a volcanically active area. Second, deformation was measured and interpreted to indicate a shallow dyke intrusion. Third, the types of earthquakes that occurred were characteristic of volcano-related seismicity.

The volcanic risk was relatively low due to the small population living near Harrat Lunayyir. On 19 June the team made a forecast that there was a moderate probability of a basaltic eruption and a low probability of additional large earthquakes of M 5 or greater occurring within the following 2 months. The forecast was based on the maximum magnitudes of earthquakes that typically accompany eruptions at other volcanoes, on the proportion of eruptions following multiple intrusions at dozens of volcanoes studied by VDAP, and on initial models of the InSAR anomaly. The team determined that the seismic swarm had ended by August 2009 when there was a decline in seismic activity and InSAR-detected deformation. After the forecast and after the buildings in Al Ays had been assessed for damage, evacuees were permitted to return to their homes.

Table 1. Chronology summarizing the 2009 Lunayyir earthquake swarm, surface rupture, and hazards response.

Date Observations and actions taken
Apr 2009 Earthquakes began
~20 Apr 2009 Evacuation started at Al Ays
29 Apr 2009 Earthquake energy increased
~12-19 May 2009 3-km-long surface rupture opened
19 May 2009 M 5.4-5.7 earthquake; surface rupture grew to 8 km long
20 May 2009 Earthquake energy decreased dramatically
Aug 2009 Earthquakes ceased
Aug 2009 Evacuees returned to Al Ays

References. Pallister, J.S., McCausland, W.A., Jonsson, S., Lu, Z., Zahran, H.M., Hadidy, S.E., Aburukbah, A., Stewart, I.C.F., Lundgren, P.R., White, R.A., and Moufti, M.R.H., 2010, Broad Accommodation of Rift-Related Extension Recorded by Dyke Intrusion in Saudi Arabia. Nature Geoscience, 26 September 2010, pp. 1-8.

SGS, 2011, Volcanism in Saudi Arabia, Saudi Geological Survey (SGS) (URL: http://www.sgs.org.sa/English/NaturalHazards/Pages/Volcanoes.aspx).

Information Contacts: John Pallister, US Geological Survey-USAID Volcano Disaster Assistance Program, 1300 SE Cardinal Court, Building 10, Suite 100, Vancouver, WA 98683-9589, USA (URL: http://volcanoes.usgs.gov/vdap/); Hani M. Zahran, National Centre for Earthquakes and Volcanoes, Saudi Geological Survey (SGS), P.O. Box: 54141, Jeddah, 21514 Saudi Arabia (URL: http://www.sgs.org.sa/English/NaturalHazards/Pages/Earthquakes.aspx).

The Global Volcanism Program has no Weekly Reports available for Harrat Lunayyir.

Bulletin Reports - Index

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

03/2011 (BGVN 36:03) 2009 seismic swarm, deformation, and 8 km surface rupture




Information is preliminary and subject to change. All times are local (unless otherwise noted)


March 2011 (BGVN 36:03) Citation IconCite this Report

2009 seismic swarm, deformation, and 8 km surface rupture

An intense seismic swarm coupled with surface deformation spurred the evacuation of over 30,000 residents, led to an 8 km long surface rupture, and was consistent with the injection of a shallow dike that never reached the surface. Between April and June 2009 more than 30,000 earthquakes occurred beneath one of the lava fields of Saudi Arabia adjacent the N-central portion of the Red Sea and centered inland ~50 km ENE from the port city of Umm Lajj (figure 1). The field is known as Harrat Lunayyir (the words harrat and haarrat indicate a volcanic field, named and unnamed, respectively). Ultimately a narrow, 8 km long surface rupture developed and the seismicity declined. The event was interpreted as due to a shallow intrusion that did not reach the surface. Table 1 at the end of this report gives an overview of the crisis, which included evacuations.

Figure (see Caption) Figure 1. Index map (at upper right focused on the Red Sea) and the main map showing numerous named volcanic fields (harrats) in Saudi Arabia, including Lunayyir. The cities of Umm Lajj and Al Ays are discussed in text. Original map taken from SGS (2011).

This report is based on Pallister and others (2010) as well as a report from scientists from the USGS-USAID Volcano Disaster Assistance Program (VDAP) and the Saudi Geological Survey (SGS). The government of Saudi Arabia evacuated more than 30,000 people from the town of Al Ays on the SE margin of the volcanic field, due to fears that further larger earthquakes could occur or that there could be a volcanic eruption (figures 2 and 3). In response to this situation, SGS increased their presence in the region and installed a permanent telemetered seismic network of seven broadband seismometers in the area to better monitor the seismicity.

Figure (see Caption) Figure 2. The town of Al Ays is shown. About 30,000 people were evacuated from the area due to the earthquake swarm. Previous lava flows of the Harrat Lunayyir volcanic field cover much of the back and central portions of the photo beyond the town. Photograph courtesy of John Pallister (VDAP).
Figure (see Caption) Figure 3. Areal view of cinder cones found at Harrat Lunayyir. Photograph courtesy of John Pallister (VDAP).

A punctuated earthquake swarm began at Harrat Lunayyir in April 2009, with a peak on 19 May when 19 earthquakes of M 4 or greater occurred. The largest of those earthquakes was variably assessed as M 5.4 (SGS) and M 5.7 (USGS National Earthquake Information Center). It struck at 1735 UTC (2035 local time). The earthquake caused minor damage to structures in the town of Al Ays (40 km SE of the epicenter).

Surface rupture. In the northern central part of the lava field the initial surface rupture extended 3 km, trended NW, and appeared during the week preceding 19 May (when maximum earthquake magnitudes exceeded M 4). Associated with the M 5.4 earthquake on 19 May, the rupture lengthened to 8 km. The rupture had local vertical offsets of more than 1 meter and was several meters deep (figures 4 and 5). Event rates decreased dramatically on 20 May and maintained a relatively constant level, except for a few increases in event rate lasting 24 hours.

Figure (see Caption) Figure 4. The 8-km-long surface rupture that opened on 19 May 2009 seen here cutting across soft sediments in the Harrat Lunayyir region. Taken from SGS (2011).
Figure (see Caption) Figure 5. Wendy McCausland (USGS-VDAP seismologist) consults with Hani Zahran (Director of Earthquake and Volcanoes Center, Saudi Geological Survey) at the site of the 8 km long surface rupture that opened during the 19 May 2009 earthquake at Lunayyir. Photograph courtesy of John Pallister (VDAP).

Combining seismic with InSAR and modeling. Results from InSAR data and geodetic modeling were consistent with the timing of the seismic swarm. InSAR data showed that 75% of the deformation occurred during 8-27 May 2009, and 20% occurred during 27 May to 17 June (figure 6). Interferograms from May and June showed a broad area of deformation of about 2,000 km2, which is indicative of dyke intrusion. Envisat interferograms showed about 40 cm of uplift and over 1 m of E-W extension.

Figure (see Caption) Figure 6. For Lunayyir, plots of real-time seismic amplitude (RSAM) for 10-min intervals showing peak seismic energy releases for the vertical component of broadband seismic stations UMGS and LNYS (45 km WSE and 29 km SE from the epicenter of the M 5.4 earthquake on 19 May). The lower graph shows daily counts of very long frequency earthquakes recorded at both stations. InSAR-detected deformation periods are indicated by shading (yellow on colored versions). Taken from Pallister and others (2010).

Earthquakes suggestive of volcanism. Initially, scientists were unsure if the earthquakes were tectonic or volcanic in origin. On 12 June two members of a VDAP team deployed to Saudia Arabia at the request of the SGS to provide technical assistance. The VDAP and SGS teams determined that the earthquake pattern was that of a volcanic earthquake swarm. It was characterized by several ten's of thousands of small (under M 3) earthquakes during 24 April-31 July 2009, in a pattern of seismicity that waxed and waned. Earthquakes occurred of both varying magnitude and lacking tectonic mainshock-aftershock sequences. RSAM (real-time seismic-amplitude measurement) data showed that energy increased dramatically on 29 April, peaking on 19 May with the previously mentioned largest (M 5.4) event.

Other common volcanic-swarm characteristics included a high rate of occurrence of small compared to large events, and shallow event locations clustered beneath the lava field at around 5-10 km in depth. The event types included those of high-frequency (13-28 Hz), very low-frequency (less than 1 Hz), and high-frequency tremor. The latter contained embedded spasmodic bursts of high-frequency earthquakes (13-28 Hz).

An unusual aspect of the swarm was that both low- and very low-frequency earthquakes occurred, events that are usually associated with movements of fluids (magma, water or gas) and Strombolian explosions, but in this case both gas emissions and explosions were absent.

The VDAP and SGS teams concluded that there were three key lines of evidence that the earthquakes were volcanic. First, the earthquakes were occurring in a volcanically active area. Second, deformation was measured and interpreted to indicate a shallow dyke intrusion. Third, the types of earthquakes that occurred were characteristic of volcano-related seismicity.

The volcanic risk was relatively low due to the small population living near Harrat Lunayyir. On 19 June the team made a forecast that there was a moderate probability of a basaltic eruption and a low probability of additional large earthquakes of M 5 or greater occurring within the following 2 months. The forecast was based on the maximum magnitudes of earthquakes that typically accompany eruptions at other volcanoes, on the proportion of eruptions following multiple intrusions at dozens of volcanoes studied by VDAP, and on initial models of the InSAR anomaly. The team determined that the seismic swarm had ended by August 2009 when there was a decline in seismic activity and InSAR-detected deformation. After the forecast and after the buildings in Al Ays had been assessed for damage, evacuees were permitted to return to their homes.

Table 1. Chronology summarizing the 2009 Lunayyir earthquake swarm, surface rupture, and hazards response.

Date Observations and actions taken
Apr 2009 Earthquakes began
~20 Apr 2009 Evacuation started at Al Ays
29 Apr 2009 Earthquake energy increased
~12-19 May 2009 3-km-long surface rupture opened
19 May 2009 M 5.4-5.7 earthquake; surface rupture grew to 8 km long
20 May 2009 Earthquake energy decreased dramatically
Aug 2009 Earthquakes ceased
Aug 2009 Evacuees returned to Al Ays

References. Pallister, J.S., McCausland, W.A., Jonsson, S., Lu, Z., Zahran, H.M., Hadidy, S.E., Aburukbah, A., Stewart, I.C.F., Lundgren, P.R., White, R.A., and Moufti, M.R.H., 2010, Broad Accommodation of Rift-Related Extension Recorded by Dyke Intrusion in Saudi Arabia. Nature Geoscience, 26 September 2010, pp. 1-8.

SGS, 2011, Volcanism in Saudi Arabia, Saudi Geological Survey (SGS) (URL: http://www.sgs.org.sa/English/NaturalHazards/Pages/Volcanoes.aspx).

Information Contacts: John Pallister, US Geological Survey-USAID Volcano Disaster Assistance Program, 1300 SE Cardinal Court, Building 10, Suite 100, Vancouver, WA 98683-9589, USA (URL: http://volcanoes.usgs.gov/vdap/); Hani M. Zahran, National Centre for Earthquakes and Volcanoes, Saudi Geological Survey (SGS), P.O. Box: 54141, Jeddah, 21514 Saudi Arabia (URL: http://www.sgs.org.sa/English/NaturalHazards/Pages/Earthquakes.aspx).

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Eruptive History

There is data available for 1 confirmed Holocene eruptive periods.

1000 (in or before) Confirmed Eruption  

Episode 1 | Eruption
1000 (in or before) - Unknown Evidence from Observations: Reported

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava flow
Deformation History

There is data available for 1 deformation periods. Expand each entry for additional details.


Deformation during 2009 May 08 - 2009 Jun 17 [Variable (subsidence / horizontal); Observed by InSAR]

Start Date: 2009 May 08 Stop Date: 2009 Jun 17 Direction: Variable (subsidence / horizontal) Method: InSAR
Magnitude: 150.000 cm Spatial Extent: Unknown Latitude: Unknown Longitude: Unknown

Remarks: Deformation associated with the 2009 rifting episode at the Harrat Lunayyir volcanic field can be modeled with two graben-bounding normal faults and a dyke.

Figure (see Caption)

(a?e) ENVISAT ASAR interferograms and (f) ALOS PALSAR interferogram for the 2009 HL swarm period. For the major deformation periods (a, b, d and f) the unwrapped phase is draped upon the corresponding wrapped fringes. Each fringe cycle corresponds to 28 mm displacement in the satellite to ground direction. For the late stages (c and e) we show only the unwrapped phase. Positive values (red) mark movement towards the satellite. White lines in (a) mark the faults. Arrows show satellite view directions and incidence angles. Note the different displacement scales for each period.

From: Baer and Hamiel 2010.


Reference List: Baer and Hamiel 2010; Pallister et al. 2010*.

Full References:

Baer G, Hamiel Y, 2010. Form and growth of an embryonic continental rift: InSAR observations and modelling of the 2009 western Arabia rifting episode. Geophysical Journal International, 182(1), 155-167.

Pallister J S, McCausland W A, Jonsson S, Lu Z, Zahran H M, El-Hadidy S, Aburukba A, Stewart I C F, Lundgren P R, White R A, Moufti M R H, 2010. Broad accommodation of rift-related extension recorded by dyke intrusion in Saudi Arabia. Nature Geosci. https://doi.org/10.1038/NGEO966

Emission History

There is no Emissions History data available for Harrat Lunayyir.

GVP Map Holdings

Maps are not currently available due to technical issues.

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included.

Smithsonian Sample Collections Database

There are no samples for Harrat Lunayyir in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

External Sites