Geological History of Baldwin Hills

The Baldwin Hills were created by tectonic forces — the slow movement of the Earth’s crust along a major fracture called the Newport–Inglewood Fault Zone. This fault is a crack in the crust where blocks of earth slide past each other. Over the last 1–2 million years, pressure along the fault slowly bent and folded layers of ancient seabed upward, forming a low ridge called an anticline. Today, this uplifted land stands out from the flatter Los Angeles Basin around it.

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• Notable fact:  The Newport–Inglewood Fault caused the 1933 Long Beach earthquake, a magnitude 6.4 event that killed 115 people and led to California’s first earthquake safety laws for schools (California Geological Survey, 2002). Lindvall & Rockwell (1995) estimated that this fault can still produce earthquakes as strong as magnitude 7.4.

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Because the Baldwin Hills sit on an active fault system, they remain sensitive to ground movement, landslides, and slow creeping shifts that can crack roads and pipelines (Treiman, 1994; Ponti et al., 2008).

 

Oil in Them Thar Hills

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The Baldwin Hills are famous for another reason: they sit on top of the Inglewood Oil Field, one of the biggest oil-producing areas in Southern California. For millions of years, dead marine life settled on the ocean floor and turned into oil and gas under heat and pressure. As tectonic forces folded and cracked the rocks, the oil migrated upward and became trapped in porous sandstones sealed by tight layers of shale.

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Oil companies began drilling here in 1924, eventually drilling more than 1,100 wells across 1,000 acres (DOGGR, 2020). Even today, dozens of active wells still pump oil from deep underground.

The 1963 Baldwin Hills Dam disaster — a catastrophic failure that released 250 million gallons of water causing five deaths — was linked to ground movement caused by oil extraction. Investigations linked the failure to subsurface oil field operations and ground movement. The field is located within a densely populated urban area, prompting decades of conflict over air quality, noise, methane emissions, and proximity to homes and schools. (Jansen et al., 1966).

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In recent years, community groups and environmental advocates have called for the field’s closure and remediation, while local agencies have increased regulation of drilling practices under environmental review mandates. Over the decades, oil operations have led to:

• Land subsidence (sinking ground)

• Air and noise pollution

• Methane gas leaks

• Conflicts with nearby communities about health and environmental justice

 

Unique Geology in a Bigger Picture

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Geologists consider the Baldwin Hills part of the Transverse Ranges, a set of mountains and ridges in Southern California that run east-west instead of the usual north-south. This unusual orientation is caused by the collision and rotation of the Pacific and North American tectonic plates (Atwater, 1998).

This big-picture tectonic activity is also why Southern California has so many active faults and why earthquakes are a constant part of life here.

 

Kizh Use of Natural Asphalt and Bitumen

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To the Kizh, the natural oil that seeped from the ground was more than a resource—it was a vital material for survival, trade, and lifeways. From the hills to the coast, tar seeps (also called bitumen or brea) emerged where petroleum naturally pushed to the surface through fractures in the rock. These deposits were commonly found in the Baldwin Hills, Ballona wetlands, and what is now known as the La Brea Tar Pits.

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Kizh families:

• Harvested asphaltum from the hills and lowlands for waterproofing tools, baskets, and most importantly, plank ocean canoes.

• Mixed the natural bitumen with plant fiber or sand to improve its strength and durability.

• Used it to seal ceremonial vessels, gourd containers, and stone tools.

• Traded tar-based materials with neighboring tribes, linking the Kizh to vast Indigenous trade networks that extended up and down the coast and inland across the mountains and into the southwestern deserts.

• The Baldwin Hills were an important gathering area not just for plant food and ceremonial observation points, but as a reliable source of natural petroleum, crucial to the marine-based technology that enabled travel between the mainland and the Channel Islands.

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Impacts on the Land and Kizh Sacred Sites

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With the industrialization of the land, the hills once used by Kizh people for ceremony, gathering, and material production were heavily disturbed:

• Natural seeps were capped or drained.

• Hillsides were terraced and fragmented by roads, derricks, and pipelines.

• Cultural gathering places and ecological corridors were lost to extraction zones.

• Earth movements caused by oil withdrawal have led to subsidence and slope instability, including the Baldwin Hills Dam failure of 1963.

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Despite these harms, the Kizh memory of the land endures. Today, Kizh cultural practitioners and environmental stewards are advocating for the returning of the hills to a state where ceremony, ecology, and cultural use can thrive again.

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The Baldwin Hills are a living laboratory for:

• Earthquake research

• Urban ecology

• Environmental justice

• Cultural resilience

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As calls grow to phase out oil extraction and restore the landscape, these hills remain a reminder that geology, ecology, and human history are inseparable.

 

 

 

 

 

 

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