Morocco's Al Haouz Earthquake: Lessons from 2023

At 11:11 PM on September 8, 2023, most residents of the High Atlas Mountains southwest of Marrakech were asleep in their homes. The mountains here — the Toubkal massif and its surrounding valleys in Al Haouz Province — are among the most scenically dramatic in North Africa: steep rocky slopes, narrow stream valleys, and clusters of earthen villages clinging to hillsides, built from the warm terracotta-colored pisé (rammed earth) that has been the dominant construction material in the Atlas for centuries. These villages — Imi n'Tala, Amizmiz, Moulay Brahim, Tizi n'Test — are places of genuine cultural and architectural antiquity, their narrow lanes and flat-roofed earthen houses unchanged in their essential character for generations. They are also, as an M6.8 earthquake at 18 km depth demonstrated in approximately 25 seconds of shaking, among the most seismically lethal building environments on Earth.

The final death toll from the 2023 Al Haouz earthquake reached 2,960 people — Morocco's deadliest earthquake since the 1960 Agadir earthquake killed approximately 12,000 people and the deadliest in North Africa since the 2003 Boumerdes earthquake in Algeria (2,266 deaths). The damage was concentrated in the remote Berber villages of the High Atlas at elevations of 1,500–2,500 meters, where the combination of near-epicentral distance, shallow source depth, and universal pisé construction produced collapse rates of 50–80% in the most affected communities. In Marrakech — 70 km from the epicenter, Morocco's fourth-largest city and one of the world's great historic cities — the earthquake severely damaged significant portions of the UNESCO-listed medina, including the collapse of minarets, sections of the city's ancient walls, and damage to hundreds of the riad courtyard houses that constitute the fabric of the historic center.

The 2023 Al Haouz earthquake was not, in seismological terms, an exceptional event — M6.8 is a significant earthquake, but not in the same category as the M8.5 events of the Nankai Trough scenarios or the M9 events of the Cascadia discussion. Its lethality was a product of the building stock it tested, the terrain it traversed, and the inadequacy of seismic hazard characterization for the Atlas Mountain region — a zone that the historical earthquake record marks as active but that had not experienced a major damaging event in the modern era, producing exactly the complacency-amplified-by-vulnerability combination that makes moderate earthquakes catastrophic throughout this series.

The Tectonic Setting: Africa Pressing into Europe — the Southern View

Morocco sits on the African (Nubian) plate — the same plate whose slow convergence into Eurasia drives the seismicity of Portugal's Azores-Gibraltar fracture zone and southern Spain's Betic Cordillera, discussed in the preceding chapters. From the North African perspective, the plate boundary manifests differently: Morocco is in the interior of the African plate, far from the actual Eurasia-Africa plate boundary, yet it experiences meaningful seismicity from the intraplate compression transmitted southward through the Moroccan lithosphere from the convergence zone offshore.

The High Atlas Mountains — Morocco's principal mountain range, running northeast-southwest across the country from near Agadir to the Algerian border — are the primary onshore expression of this Africa-Eurasia convergence in Morocco. The Atlas formed primarily in the Cenozoic through the same broad convergence event that built the Alps and the Pyrenees to the north, and its active fault systems — predominantly NE-trending reverse and thrust faults accommodating northwest-directed compression — are the structures responsible for both the mountain range's continued uplift and the region's seismicity.

Pisé Construction: Why the Atlas Villages Collapsed

To understand the 2023 earthquake's death toll, one must understand pisé — the rammed-earth construction technique that is the dominant building material in the High Atlas Mountains and in much of Morocco's rural and traditional urban fabric. Pisé (from the French, derived from the Arabic tiz, meaning "to trample") is made by ramming moist local soil — mixed in the Atlas with small stones and sometimes straw — between temporary wooden formwork to create thick, monolithic earth walls that dry to a hard but brittle consistency. The resulting walls are thermally excellent — warm in winter, cool in summer — aesthetically beautiful, and made entirely from local materials at essentially zero cost. They are also, under lateral earthquake loading, extraordinarily fragile.

Pisé has essentially zero tensile strength — the same fundamental limitation as mud brick, adobe, unreinforced masonry, and every other earthen building material discussed in this series. In an earthquake, the lateral forces applied to pisé walls exceed their shear and tensile capacity within seconds of strong shaking onset, and the walls fail — cracking diagonally, then toppling inward or outward — under the weight of the flat earth roofs they support. The flat earth roofs of Atlas village houses, like the flat earth roofs of Afghan mud-brick described in the Afghanistan chapter, are thermally and economically appropriate for the climate and the available materials — and they represent hundreds of kilograms per square meter of crushing mass that falls onto building occupants when the walls fail. In the villages within 30 km of the 2023 epicenter, where peak ground accelerations reached 0.3–0.5g, essentially no pisé building survived intact.

Why Traditional Construction Is Simultaneously Cultural Heritage and Lethal Hazard

The tension between architectural heritage preservation and seismic safety is nowhere more acute than in the High Atlas villages that were devastated in 2023. These buildings are not merely old houses — they are the material expression of a Berber building culture extending centuries, integrated with the terraced agriculture, the water management systems, and the spatial organization of mountain communities in ways that concrete replacement construction cannot replicate. Post-earthquake surveys noted, with a mixture of practical and cultural anguish, that the two or three reinforced concrete frame buildings that existed in some affected villages — typically a school or a government office built with international development funding — survived the earthquake intact while the surrounding traditional houses collapsed. The implication is clear from a purely structural standpoint: concrete beats pisé in seismic performance. The implication is considerably less clear from a cultural, economic, and community autonomy standpoint.

The reconstruction debate that followed the 2023 earthquake — whether to rebuild in traditional pisé (with improved seismic detailing: horizontal timber or concrete bond beams at wall plate height, corner reinforcement, roof-to-wall ties) or to replace traditional construction with concrete frame — replicated debates that have occurred after every major earthen-construction earthquake in this series, from Pakistan's dhajji dewari to Nepal's school retrofits to Afghanistan's band beams. The weight of evidence from post-earthquake reconstruction programs globally supports the improved traditional construction approach: it preserves cultural continuity, uses local skills and materials, and achieves meaningful seismic improvement without the full economic and cultural cost of wholesale construction replacement. The challenge is ensuring that "improved traditional" means genuinely structurally improved, not just cosmetically similar.

Marrakech: UNESCO Heritage and Seismic Exposure

The earthquake's impact in Marrakech — 70 km from the epicenter, experiencing MMI VII in the most heavily shaken parts of the city — illuminated a dimension of seismic risk that extends beyond casualties to encompass one of the world's most significant concentrations of Islamic architectural heritage.

Marrakech's medina — the historic walled city, inscribed on the UNESCO World Heritage List since 1985 — is a dense urban fabric of riad courtyard houses, mosques, hammams, and souks built predominantly from the same pisé and fired brick construction as the Atlas villages, though in a more densely packed urban configuration. The medina's buildings span several centuries of construction — from the Koutoubia Mosque minaret (12th century), to Medersa Ben Youssef (14th century, substantially rebuilt 16th), to the warren of residential buildings whose construction dates span the full Moroccan historical period. None of these structures were designed to any seismic standard, and the oldest and most architecturally significant among them are precisely the most seismically vulnerable: unreinforced masonry of the greatest age with the most degraded mortar and the most accumulated deferred maintenance.

The 2023 earthquake collapsed sections of Marrakech's historic ramparts — the 12th-century Almohad walls that enclose the medina — damaged several historic mosques, and caused the partial or complete collapse of hundreds of residential buildings within the medina. The Koutoubia Mosque itself — Marrakech's defining landmark, built in the 12th century and a masterpiece of Moroccan Islamic architecture — sustained damage to its minaret that required immediate stabilization. The earthquake thus presented UNESCO, the Moroccan Ministry of Culture, and international conservation organizations with the same dilemma faced by Quito, Kathmandu, Lisbon, and Lorca: how to preserve architectural heritage that is also a seismic liability, how to retrofit structures whose cultural significance prohibits the structural interventions that would make them safe.

Morocco's Seismic Hazard Context

The 2023 Al Haouz earthquake was Morocco's most damaging since 1960, but it was not a geological surprise in the broad sense — Morocco's seismic hazard has been documented for decades and the country has a long historical record of damaging earthquakes that clearly establishes the active nature of its fault systems.

The 1960 Agadir earthquake (M5.7–5.9 at extremely shallow depth, 2–3 km, directly beneath the city center) killed approximately 12,000 people — a shocking toll for such a moderate magnitude, but explained entirely by the combination of shallow depth, direct urban epicenter, and the predominantly unreinforced masonry building stock of 1960s Morocco. Agadir was rebuilt after 1960 to the first modern Moroccan building code that included seismic provisions — and the rebuilt city has performed substantially better in subsequent regional events. The 2004 Al Hoceima earthquake in northern Morocco (M6.3) killed 628 people in the Rif Mountains — another demonstration that Morocco's inland mountain regions contain active fault systems capable of significant events.

Morocco's Building Code and Its Gaps

Morocco adopted its first seismic building code — the RPS 2000 (Règlement de Construction Parasismique) — in 2002, following the 2000 revisitation of the lessons of Agadir 1960. The RPS 2000 was updated to RPS 2011 and incorporates seismic design provisions for reinforced concrete structures based on seismic zone classifications derived from probabilistic hazard maps of Morocco developed by the Centre National pour la Recherche Scientifique et Technique (CNRST) and international partners. Morocco's seismic zonation under RPS 2011 assigns the highest design accelerations to the northern Rif Mountains (Zone 3) and lower values to the High Atlas (Zone 2), reflecting the higher historical seismicity of the Rif relative to the Atlas at the time the hazard maps were developed.

The critical limitations of Morocco's seismic preparedness framework are threefold. First, the RPS code applies to new engineered construction in urban areas — it does not cover traditional pisé construction in rural mountain communities, which is built by local artisans without any engineering oversight or building permit process. Second, the seismic hazard maps on which the code is based underrepresented the High Atlas due to the fault mapping gap described above — the Tizi n'Test fault and comparable structures were not adequately characterized, producing design acceleration values for the Atlas region that were lower than the 2023 earthquake demonstrated was appropriate. Third, enforcement of code compliance even in urban areas where the code nominally applies is inconsistent — Morocco's construction sector has the familiar developing-country gap between code provisions and actual practice that characterizes virtually every non-OECD country covered in this series.

The Reconstruction Challenge

The reconstruction of the 2023-affected High Atlas communities presents one of the most complex post-earthquake recovery challenges of the decade — not primarily in engineering terms, but in the social, cultural, and institutional dimensions that determine whether reconstruction actually reduces future seismic vulnerability or simply rebuilds it.

The Moroccan government's initial reconstruction framework — announced within weeks of the earthquake with substantial financial commitments — proposed replacing destroyed pisé houses with reinforced concrete frame construction. International earthquake engineering NGOs and conservation organizations immediately engaged to argue for improved traditional construction alternatives, citing the evidence from Pakistan, Nepal, and Afghanistan that improved earthen construction can achieve meaningful seismic improvement while preserving cultural continuity. The technical capacity to implement improved traditional construction at the scale required — thousands of houses across dozens of remote mountain communities — requires training local masons in specific seismic detailing techniques (horizontal bond beams, corner reinforcement, roof ties) and establishing quality control processes in settings without building inspectors or permit systems.

Conclusion

The 2023 Al Haouz earthquake is, in the typology of this series, a classic moderate-magnitude/catastrophic-consequence event — M6.8 producing nearly 3,000 deaths because the building stock it tested offered no structural resistance to lateral shaking. The pisé of the Atlas mountains is not structurally different from the mud brick of Afghanistan, the black cotton soil construction of Maharashtra, or the adobe of rural Ecuador: all are materials that provide gravity resistance without seismic resistance, and all produce the same catastrophic failure pattern when earthquake loading is applied. The geography differs. The cultural context differs. The death toll differs in proportion to the local seismicity and population density. The physics is identical.

The lessons of 2023 are specific and actionable. Active fault mapping in North Africa requires investment comparable to the systematic geological surveys conducted in Japan, California, and New Zealand — not because North Africa faces the same hazard levels but because unmapped active faults kill people who assumed they were safe. Improved traditional construction — earthen building with horizontal bond beams and roof connections — can substantially reduce mortality in the mountain communities that will always build with local materials. Emergency access infrastructure — pre-positioned rescue equipment, helicopter-accessible staging, robust mountain road networks — can reduce the "golden 72 hours" access problem that determined many deaths in 2023. And the Marrakech medina's heritage and seismic vulnerability require the same difficult retrofit conversation that Kathmandu, Quito, and Lisbon are having about their own historic building stock — a conversation that the 2023 earthquake has finally made impossible to defer.