DOI: 10.17603/ds2-gw0j-6757
title: StEER: Oukaïmedene Morocco Preliminary Virtual Reconnaissance Report (PVRR)
title: in StEER 2023 Oukaïmedene Morocco Earthquake

description: In light of the impacts, StEER activated a Level 1 response to this earthquake and formed a Virtual Assessment Structural Team (VAST) to assemble this Preliminary Virtual Reconnaissance Report (PVRR), intended to:
(1) Overview the 2023 Morocco earthquake and its impact on the built environment;
(2) Summarize the codes regulations and construction practices in the affected area;
(3) Synthesize preliminary reports of damage to structures; 
(4) Recommend priorities for continued study and action.
description: On September 8, 2023, at 11:11 pm local time, a magnitude Mw 6.8 earthquake occurred in Morocco’s High Atlas mountain range, with a focal depth of 26 km. The earthquake was followed by several aftershocks, including a magnitude Mw 4.9 aftershock that occurred 19 minutes after the mainshock. The earthquake resulted in nearly 3,000 casualties and damaged or collapsed tens of thousands of structures.
This earthquake was not only the strongest in Morocco in the past century, but it also resulted in shaking beyond the Design Basis Earthquake (DBE) level in Morocco. With a DBE of up to 0.18g in the seismic hazard maps, the impacted region was considered to have low-to-moderate seismicity, which may be the result of limited long-term earthquake observations in this region. There were no recorded ground motions of this event, which will further hinder the ability to learn from this disaster. Thus, this earthquake underscored the need for such monitoring as a key element of efforts to update seismic hazard quantification and mapping in Morocco, including establishing Maximum Considered Earthquake (MCE) levels.
Regardless, the vulnerabilities of traditional earthen buildings were evident, with various expected failure mechanisms, including in-plane and out-of-plane collapse with wall detachment from floors. Other vulnerable building types, including non-ductile concrete and unreinforced masonry buildings, experienced expected levels of damage. Unfortunately, there were textbook examples of complete/partial collapse, including soft-story collapses and overturning failures due to insufficient foundations. Beyond this region being historically characterized as having low- to mid-level seismicity, these failures underscore the lack of aseismic design knowledge.
The earthquake also tragically impacted a large number of historical structures. The structural condition of 27 monuments has been classified as heavily to very heavily damaged (partially collapsed). The types of damage varied from significant cracks to partial collapse of the structures. Among the partially collapsed historical structures was the Historical Tinmel Mosque, a national monument constructed in the year 1124 and a site on the tentative list of UNESCO World Heritage Sites since 1995. The observed damage and collapses once again highlight the need to develop innovative and effective methods for retrofitting historical structures while preserving their historical and cultural identity.
On a positive note, all hospitals were undamaged and functional after the earthquake. This is partly because there was no hospital in the near-fault region. However, whether this positive performance was due to low levels of ground shaking or sound aseismic design cannot be fully ascertained due to the absence of strong motion stations. This underscores the opportunity to develop ground motion instrumentation networks through low-cost sensor solutions, which can also be expanded to instrument structures to characterize their response.

In light of these impacts, StEER activated a Level 1 response to this earthquake and formed a Virtual Assessment Structural Team (VAST) to assemble this Preliminary Virtual Reconnaissance Report (PVRR), intended to:
Overview the 2023 Morocco earthquake and its impact on the built environment;
Summarize the codes, regulations and construction practices in the affected area;
Synthesize preliminary reports of damage to structures; 
Recommend priorities for continued study and action.

This project encompasses the products of StEER's Level 1 response to this event: Preliminary Virtual Reconnaissance Report (PVRR) with corresponding Media Repository.